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Author name code: kopp-greg
ADS astronomy entries on 2022-09-14
author:"Kopp, Greg A."
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Title: Variability of the Sun's Luminosity Places Constraints on
the Thermal Equilibrium of the Convection Zone
Authors: Vieira, L. E. A.; Kopp, G.; Dudok de Wit, T.; da Silva,
L. A.; Carlesso, F.; Barbosa, A. R.; Muralikrishna, A.; Santos, R.
2022ApJS..260...38V Altcode: 2022arXiv220402940V
Luminosity, which is the total amount of radiant energy emitted by
an object, is one of the most critical quantities in astrophysics for
characterizing stars. Equally important is the temporal evolution of a
star's luminosity because of its intimate connection with the stellar
energy budget, large-scale convective motion, and heat storage in the
stellar interior. The Sun's luminosity and its variation have not been
measured to date because current observations of the solar radiative
output have been restricted to vantage points near the Earth. Here,
we model the solar luminosity by extending a semiempirical total solar
irradiance (TSI) model that uses solar-surface magnetism to reconstruct
solar irradiance over the entire 4π solid angle around the Sun. This
model was constrained by comparing its output to the irradiance in the
Earth's direction with the measured TSI. Comparing the solar luminosity
to the TSI on timescales from days to solar cycles for cycles 23 and 24,
we find poor agreement on short timescales (<solar rotation). This is
not unexpected due to the Earth-centric viewing geometry and short-term
irradiance dependence on surface features on the Earth-facing solar
disk. On longer timescales, however, we find good agreement between
the luminosity model and the TSI, which suggests that the extrapolation
of luminosities to multicycle timescales based on TSI reconstructions
may be possible. We show that the solar luminosity is not constant but
varies in phase with the solar cycle. This variation has an amplitude
of 0.14% from minimum to maximum for Solar Cycle 23. Considering the
energetics in the solar convection zone, it is therefore obvious that
a steady-state input from the radiative zone at the solar minimum
level would lead to a gradual reduction in the energy content in
the convection zone over multicentury timescales. We show that the
luminosity at the base of the convection zone should be approximately
0.032% higher than that at the solar surface during solar minimum
to maintain net energy equilibrium through the solar cycle. These
different energy-input scenarios place constraints on the long-term
evolution of the TSI and its impact on the solar forcing of climate
variability. These results highlight the convection zone's role as
an energy reservoir on solar-cycle timescales and set constraints for
dynamo models intending to understand the long-term evolution of the
Sun and solar analogs.
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Title: Solar-Cycle Variability Results from the Solar Radiation and
Climate Experiment (SORCE) Mission
Authors: Woods, Thomas N.; Harder, Jerald W.; Kopp, Greg; Snow, Martin
2022SoPh..297...43W Altcode:
The Solar Radiation and Climate Experiment (SORCE) was a NASA mission
that operated from 2003 to 2020 to provide key climate-monitoring
measurements of total solar irradiance (TSI) and solar spectral
irradiance (SSI). This 17-year mission made TSI and SSI observations
during the declining phase of Solar Cycle 23, during all of Solar
Cycle 24, and at the very beginning of Solar Cycle 25. The SORCE
solar-variability results include comparisons of the solar irradiance
observed during Solar Cycles 23 and 24 and the solar-cycle minima
levels in 2008 - 2009 and 2019 - 2020. The differences between these two
minima are very small and are not significantly above the estimate of
instrument stability over the 11-year period. There are differences in
the SSI variability for Solar Cycles 23 and 24, notably for wavelengths
longer than 250 nm. Consistency comparisons with SORCE variability on
solar-rotation timescales and solar-irradiance model predictions suggest
that the SORCE Solar Cycle 24 SSI results might be more accurate than
the SORCE Solar Cycle 23 results. The SORCE solar-variability results
have been useful for many Sun-climate studies and will continue to
serve as a reference for comparisons with future missions studying
solar variability.
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Title: Final Report for SAG 21: The Effect of Stellar Contamination
on Space-based Transmission Spectroscopy
Authors: Rackham, Benjamin V.; Espinoza, Néstor; Berdyugina, Svetlana
V.; Korhonen, Heidi; MacDonald, Ryan J.; Montet, Benjamin T.; Morris,
Brett M.; Oshagh, Mahmoudreza; Shapiro, Alexander I.; Unruh, Yvonne C.;
Quintana, Elisa V.; Zellem, Robert T.; Apai, Dániel; Barclay, Thomas;
Barstow, Joanna K.; Bruno, Giovanni; Carone, Ludmila; Casewell, Sarah
L.; Cegla, Heather M.; Criscuoli, Serena; Fischer, Catherine; Fournier,
Damien; Giampapa, Mark S.; Giles, Helen; Iyer, Aishwarya; Kopp, Greg;
Kostogryz, Nadiia M.; Krivova, Natalie; Mallonn, Matthias; McGruder,
Chima; Molaverdikhani, Karan; Newton, Elisabeth R.; Panja, Mayukh;
Peacock, Sarah; Reardon, Kevin; Roettenbacher, Rachael M.; Scandariato,
Gaetano; Solanki, Sami; Stassun, Keivan G.; Steiner, Oskar; Stevenson,
Kevin B.; Tregloan-Reed, Jeremy; Valio, Adriana; Wedemeyer, Sven;
Welbanks, Luis; Yu, Jie; Alam, Munazza K.; Davenport, James R. A.;
Deming, Drake; Dong, Chuanfei; Ducrot, Elsa; Fisher, Chloe; Gilbert,
Emily; Kostov, Veselin; López-Morales, Mercedes; Line, Mike; Močnik,
Teo; Mullally, Susan; Paudel, Rishi R.; Ribas, Ignasi; Valenti, Jeff A.
2022arXiv220109905R Altcode:
Study Analysis Group 21 (SAG21) of the Exoplanet Exploration Program
Analysis Group (ExoPAG) was organized to study the effect of stellar
contamination on space-based transmission spectroscopy, a method for
studying exoplanetary atmospheres by measuring the wavelength-dependent
radius of a planet as it transits its star. Transmission spectroscopy
relies on a precise understanding of the spectrum of the star being
occulted. However, stars are not homogeneous, constant light sources
but have temporally evolving photospheres and chromospheres with
inhomogeneities like spots, faculae, and plages. This SAG has brought
together an interdisciplinary team of more than 100 scientists, with
observers and theorists from the heliophysics, stellar astrophysics,
planetary science, and exoplanetary atmosphere research communities,
to study the current needs that can be addressed in this context to
make the most of transit studies from current NASA facilities like
HST and JWST. The analysis produced 14 findings, which fall into
three Science Themes encompassing (1) how the Sun is used as our best
laboratory to calibrate our understanding of stellar heterogeneities
("The Sun as the Stellar Benchmark"), (2) how stars other than the Sun
extend our knowledge of heterogeneities ("Surface Heterogeneities of
Other Stars") and (3) how to incorporate information gathered for the
Sun and other stars into transit studies ("Mapping Stellar Knowledge
to Transit Studies").
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Title: Four, Three, Two, One... Whats Up (or Down) with the TSI
Instruments?
Authors: Kopp, Greg; Coddington, Odele; Dudok de Wit, Thierry; Harber,
David; Heuerman, Karl; Lean, Judith; Upton, Lisa; Wang, Yi-Ming
2021AGUFMGC24E..04K Altcode:
Over the last three years, the number of spaceborne instruments
producing measurements of the total solar irradiance (TSI), the TOA
net incoming energy powering the Earths climate system, has decreased
from four to one. This 43-year-long record of solar variability has
depended on continuity and overlap of successive instruments but is
now completely reliant on the Total Irradiance Monitor flying on the
International Space Station. Fortunately, this is a short-term trend
in this climate data record and not an intended long-term trend. We
summarize the recent turnover (or, more correctly, turn-off) causing
the declining number in the instrument suite contributing to the
TSI record. Then, before extrapolating-based panic might set in, we
provide a more optimistic look at the future of these measurements and
the several instruments currently being readied for launch, some of
which include fresh designs enabled by new materials and calibration
approaches. We will also discuss updates to a composite TSI record
using the entire collection of instruments from the spacecraft era
as well as mentioning the accuracies and stabilities of the recent
measurements. Finally, we mention an effort underway to extend the
TSI record to historical times via updates to sunspot-number records,
modern flux-transport models, and proxy-based TSI-reconstruction models.
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Title: Reconstructing solar irradiance from historical Ca II K
observations. I. Method and its validation
Authors: Chatzistergos, Theodosios; Krivova, Natalie A.; Ermolli,
Ilaria; Yeo, Kok Leng; Mandal, Sudip; Solanki, Sami K.; Kopp, Greg;
Malherbe, Jean-Marie
2021A&A...656A.104C Altcode: 2021arXiv210905844C
Context. Knowledge of solar irradiance variability is critical to
Earth's climate models and understanding the solar influence on Earth's
climate. Direct solar irradiance measurements have only been available
since 1978. Reconstructions of past variability typically rely on
sunspot data. However, sunspot records provide only indirect information
on the facular and network regions, which are decisive contributors to
irradiance variability on timescales of the solar cycle and longer. <BR
/> Aims: Our ultimate goal is to reconstruct past solar irradiance
variations using historical full-disc Ca II K observations to describe
the facular contribution independently of sunspot observations. Here,
we develop the method and test it extensively by using modern CCD-based
(charge-coupled device) Ca II K observations. We also carry out initial
tests on two photographic archives. <BR /> Methods: We employ carefully
reduced and calibrated Ca II K images from 13 datasets, including some
of the most prominent series, such as those from the Meudon, Mt Wilson,
and Rome observatories. We convert them to unsigned magnetic field
maps and then use them as input to the adapted Spectral and Total
Irradiance Reconstruction (SATIRE) model to reconstruct total solar
irradiance (TSI) variations over the period 1978-2019, for which
direct irradiance measurements are available. <BR /> Results: The
reconstructed irradiance from the analysed Ca II K archives agrees well
with direct irradiance measurements and existing reconstructions. The
model also returns good results on data taken with different bandpasses
and images with low spatial resolution. Historical Ca II K archives
suffer from numerous inconsistencies, but we show that these archives
can still be used to reconstruct TSI with reasonable accuracy provided
the observations are accurately processed and the effects of changes
in instrumentation and instrumental parameters are identified and
accounted for. The reconstructions are relatively insensitive to the
TSI reference record used to fix the single free parameter of the
model. Furthermore, even employment of a series, itself reconstructed
from Ca II K data, as a reference for further reconstructions returns
nearly equally accurate results. This will enable the Ca II K archives
without an overlap with direct irradiance measurements to be used to
reconstruct past irradiance. <BR /> Conclusions: By using the unsigned
magnetic maps of the Sun reconstructed from modern high-quality Ca
II K observations as input into the SATIRE model, we can reconstruct
solar irradiance variations nearly as accurately as from directly
recorded magnetograms. Historical Ca II K observations can also be
used for past irradiance reconstructions but need additional care,
for example identifying and accounting for discontinuities and changes
in the quality of the data with time.
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Title: Science Highlights and Final Updates from 17 Years of Total
Solar Irradiance Measurements from the SOlar Radiation and Climate
Experiment/Total Irradiance Monitor (SORCE/TIM)
Authors: Kopp, Greg
2021SoPh..296..133K Altcode:
The final version (V.19) of the total solar irradiance data from the
SOlar Radiation and Climate Experiment (SORCE) Total Irradiance Monitor
has been released. This version includes all calibrations updated to the
end of the mission and provides irradiance data from 25 February 2003
through 25 February 2020. These final calibrations are presented along
with the resulting final data products. An overview of the on-orbit
operations timeline is provided as well as the associated changes
in the time-dependent uncertainties. Scientific highlights from the
instrument are also presented. These include the establishment of a
new, lower TSI value; accuracy improvements to other TSI instruments
via a new calibration facility; the lowest on-orbit noise (for
high sensitivity to solar variability) of any TSI instrument; the
best inherent stability of any on-orbit TSI instrument; a lengthy
(17-year) measurement record benefitting from these stable, low-noise
measurements; the first reported detection of a solar flare in TSI;
and observations of two Venus transits and four Mercury transits.
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Title: Overview of the Solar Radiation and Climate Experiment (SORCE)
Seventeen-Year Mission
Authors: Woods, Thomas N.; Harder, Jerald W.; Kopp, Greg; McCabe,
Debra; Rottman, Gary; Ryan, Sean; Snow, Martin
2021SoPh..296..127W Altcode:
The Solar Radiation and Climate Experiment (SORCE) was a NASA mission
that operated from 2003 to 2020 to provide key climate-monitoring
measurements of total solar irradiance (TSI) and solar spectral
irradiance (SSI). Three important accomplishments of the SORCE mission
are i) the continuation of the 42-year-long TSI climate data record,
ii) the continuation of the ultraviolet SSI record, and iii) the
initiation of the near-ultraviolet, visible, and near-infrared SSI
records. All of the SORCE instruments functioned well over the 17-year
mission, which far exceeded its five-year prime mission goal. The SORCE
spacecraft, having mostly redundant subsystems, was also robust over the
mission. The end of the SORCE mission was a planned passivation of the
spacecraft following a successful two-year overlap with the NASA Total
and Spectral Solar Irradiance Sensor (TSIS) mission, which continues
the TSI and SSI climate records. There were a couple of instrument
anomalies and a few spacecraft anomalies during SORCE's long mission,
but operational changes and updates to flight software enabled SORCE
to remain productive to the end of its mission. The most challenging of
the anomalies was the degradation of the battery capacity that began to
impact operations in 2009 and was the cause for the largest SORCE data
gap (August 2013 - February 2014). An overview of the SORCE mission is
provided with a couple of science highlights and a discussion of flight
anomalies that impacted the solar observations. Companion articles
about the SORCE instruments and their final science data-processing
algorithms provide additional details about the instrument measurements
over the duration of the mission.
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Title: Measuring and modeling the variability of solar Balmer lines
Authors: Criscuoli, S.; Marchenko, S.; Deland, M.; Choudhary, D.;
Kopp, G.
2021AAS...23811312C Altcode:
We investigate the variability of solar Balmer lines (H-alpha,
beta, gamma, delta) observed by space-borne radiometers (SORCE,
SCIAMACHY, GOME-2, OMI, and TROPOMI), combining these precise,
long-term observations with abundant, high-resolution data from the
ground-based NSO/ISS spectrograph. We relate the detected variability
to the appearance of magnetic features on the solar disk. We find that
on solar-rotation timescales Balmer line activity indices (defined as
line-core to line-wing ratios) closely follow variations in the total
solar irradiance (which is predominantly photospheric), thus frequently
(specifically, during passages of big sunspot groups) deviates from
behavior of the line-activity indices that track chromospheric activity
levels. At longer timescales (years), the correlation with chromospheric
indices increases, with periods of low- or even anti- correlation found
at intermediate timescales. Comparisons with Balmer-line variability
patterns obtained from a semi-empirical model indicate that it is
unlikely that the periods of low/anti correlations can be ascribed to
the presence of filaments, in contradiction to some previous studies.
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Title: Historical TSI Reconstructions: Calibrating the Polar Fields
in the Advective Flux Transport Model Using Joy's Law Tilt
Authors: Upton, L.; Coddington, O.; Kopp, G.; Lean, J.
2021AAS...23830407U Altcode:
Historical reconstructions of total solar irradiance (TSI) rely
on estimates of the solar open and closed magnetic flux obtained
by simulating the flux emergence and transport. The Advective Flux
Transport (AFT) model is a realistic surface flux transport model that
has demonstrated its ability to reproduce flux emergence and evolution
on the Sun. We have created synthetic active region databases based on
the Sunspot Indices and Long-term Solar Observations (SILSO) 2.0 revised
sunspot-number record. These synthetic databases include the timing,
position, Joy's tilt, and strength of solar active regions and have been
used as input into AFT to create historical reconstructions. While these
reconstructions produce realistic magnetic maps and solar cycles with
alternating Hale's polarity, the change in the polar axial dipole (which
is the basis for the estimates of the open flux) from the beginning of
the cycle to the end of the cycle was weaker than expected. We show
that modifying the distribution of Joy's Law tilt (i.e., the scatter
about the standard Joy's Law tilt) allows us to modulate the rate at
which the polar fields change. In particular, we find that increasing
the variability in Joy's Law tilt significantly increases the change
in the polar axial dipole from one cycle to the next. We have used
the observed relationship between the strength of the polar fields
at minimum and the amplitude of the next solar cycle to estimate how
much the axial dipolar fields should change over the course of each
historical cycle. We then modify the Joy's Law tilt distribution in
each cycle to ensure that desired change in the polar fields for that
cycle is achieved. In this way, we are able to calibrate the polar
field evolution in the simulations to produce more realistic solar
cycles. Finally, we show the impact that these changes have on the
historical reconstructions of TSI.
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Title: Irradiance Variations of the Sun and Sun-Like Stars - Overview
of Topical Collection
Authors: Kopp, Greg; Shapiro, Alexander
2021SoPh..296...60K Altcode: 2021arXiv210206913K
This topical collection summarizes recent advances in observing
and modeling irradiance variations of the Sun and Sun-like stars,
emphasizing the links between surface magnetic fields and the resulting
solar and stellar variability. In particular, the articles composing
this collection summarize recent progress in i) solar-irradiance
measurements; ii) modeling of solar- and stellar-irradiance variability;
and iii) understanding of the effects of such variability on Earth's
climate and exoplanet environments. This topical-collection overview
article gives background and more details on these aspects of
variability.
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Title: Understanding variability of solar Balmer lines
Authors: Criscuoli, Serena; Marchenko, Sergey; DeLand, Matthew;
Choudary, Debi; Kopp, Greg
2021csss.confE.290C Altcode:
Precise, adequately high-cadence, long-term records of spectral
variability at different temporal scales lead to better understanding of
a wide variety of phenomena including stellar atmospheres and dynamos,
evolution of the magnetic fields on a stellar photosphere, convective
motions, and rotational periods. These, in turn, are fundamental
for the detectability of exoplanets, the characterization of their
atmospheres and habitability, as well as characterization of stellar
magnetospheres and winds. The Sun, viewed as a star via spectral
irradiance measurements, offers a means of exploring such measurements
while also having the imaging capability to help discern the causes
of observed spectral variations. In this study, we investigate the
variability of solar Balmer lines (H-α, β, γ and δ) observed by
space-borne radiometers, combining these precise, long-term observations
with abundant, high-resolution data from the ground-based NSO/ISS
spectrograph. We relate the detected variability to magnetic features
on the solar disk. We find that on solar-rotation timescales (~month),
the Balmer line activity indices (defined as line-core to line-wing
ratios) closely follow variations in the total solar irradiance
(which is predominantly photospheric), thus frequently (specifically,
during passages of big sunspot groups) deviates from behavior of the
line-activity indices that track chromospheric activity levels. At
longer timescales (years), the correlation with chromospheric indices
increases, with periods of low- or even anti- correlation found at
intermediate timescales. Comparisons with Balmer-line variability
patterns obtained from a semi-empirical model indicate the periods
of low/anti correlations should be attributed to the increase of the
relative abundance of network, which affects the Ca-index while leaving
almost un-altered the Hα-index.
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Title: Solar activity and responses observed in Balmer lines
Authors: Marchenko, S.; Criscuoli, S.; DeLand, M. T.; Choudhary,
D. P.; Kopp, G.
2021A&A...646A..81M Altcode:
Context. Many stars show Sun-like magnetic activity cycles, which
are frequently observed by tracking changes in the chromospherically
sensitive CaII H&K doublet. However, relationships between the
line profile changes related to the magnetic activity seen in strong
spectral transitions in other portions of a stellar spectrum are
yet to be understood. <BR /> Aims: We follow variability patterns in
various solar lines in order to relate them to the emergence, passage,
and decay of active solar regions. <BR /> Methods: The line activity
indices (core-to-wing ratio) for the upper Balmer lines - Hβ, Hγ,
and Hδ - are constructed from the near-daily solar measurements
acquired by the Ozone Monitoring Instrument and the TROPOspheric
Monitoring Instrument. <BR /> Results: On solar rotation timescales,
the upper Balmer line activity indices closely follow variations in
the total solar irradiance, r ∼ -(0.6 - 0.7), and thus frequently
deviate from the behavior of the line activity indices that track
chromospheric activity levels (e.g., the CH 430 nm band used in this
study), specifically during passages of big sunspot groups.
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Title: Historical Solar Irradiance Using the Updated Sunspot Record
Authors: Kopp, G.; Coddington, O.; Lean, J.; Upton, L.
2020AGUFMA227.0006K Altcode:
The total solar irradiance (TSI), which is by far the largest
contributor to the energy input to the Earth's climate system, has
been measured from space for the last four decades. Earth-climate
studies rely on long-duration records, for which this is only
beginning to qualify. To extend this record back in time and
enable lengthier correlations with other Earth-climate data records,
solar-irradiance models are used. One such is the NRLTSI model, which
uses TSI measurement-era correlations with solar proxies to estimate
historical TSI values via the temporal extensions enabled by those
proxies. The longest-duration direct-measurement solar proxy is the
sunspot record, which spans over 400 years now. Reevaluations of that
record via reanalyzes of the original data records, the discovery of new
sunspot records, and different combinations of observers' records via
new analytical methods have led to the Solar Index and Long-term Solar
Observations (SILSO) V.2 sunspot record. This new record, shown in red
in the figure, shows much higher sunspot counts and different temporal
variability than the prior (V.1) record (shown in green in the figure).
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Title: Changing of the Guard for Total Solar Irradiance
Authors: Kopp, G.
2020AGUFMA237...05K Altcode:
The Total Irradiance Monitor (TIM) on the SORCE mission established an
accuracy of total solar irradiance (TSI) measurements that was about
ten times better than previous instruments achieved. The instrument
also demonstrated improvements in inherent stability, being four
to twenty times better than other spacecraft instruments. Both of
these achievements are due to an improved design over prior such
instruments. The SORCE/TIM continued on to achieve several other notable
accomplishments, including the first detection of a solar flare in TSI,
measuring the largest short-term solar-irradiance decrease recorded
during the spacecraft era, and observing six planetary transits. Its
primary accomplishment, however, may be contributing one of the
longest-duration time series of the TSI to the critical solar-climate
data record, being 17 years (and one day) long (shown in red in the
figure). <P />The fourth successor to this innovative and stalwart
instrument has now been built and launched. The TSIS-1/TIM began
regular measurements in early 2018, providing two years of overlap with
the SORCE/TIM before the latter was decommissioned in Feb. 2020. The
TSIS-1/TIM has improved accuracies over those of even the SORCE/TIM,
and is currently the only TSI instrument providing publicly-available
data to maintain the 42-year-long spaceborne TSI measurement record.
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Title: 1/f noise in irradiance records affects our understanding of
trends in solar radiative forcing
Authors: Dudok de Wit, T.; Kopp, G.
2020AGUFMA237...08D Altcode:
One of the critical issues in solar irradiance observations is the
making of records that are long enough to 1) have sufficient overlap
between different missions to determine instrument offsets and 2) to
distinguish actual solar trends from instrumental effects. Different
approaches have been developed for quantifying the minimal duration
of such records or for determing when a perceived trend is real. <P
/>Recently, we have found that the noise of total solar irradiance
radiometers tends to follow a 1/f scaling, which is also known as
flicker noise. 1/f noise stands out by having long-range correlations
and properties that are substantially different from the usual (and
often implicitly assumed) white noise. Here we show how this 1/f noise
deeply impacts our perception of trends in irradiance observations,
whose assessment requires much greater care.
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Title: NASA's Solar Radiation and Climate Experiment (SORCE) Final
Data Products of Solar Irradiance from 2003 to 2020
Authors: Sandoval, L.; Merkel, A. W.; Beland, S.; Penton, S. V.;
Stone, B.; Elliott, J. P.; Harder, J. W.; Snow, M. A.; Kopp, G.;
McClintock, W. E.; Woods, T. N.
2020AGUFMA227.0010S Altcode:
The Spectral Irradiance Monitor (SIM), the SOlar Stellar Irradiance
Comparison Experiment (SOLSTICE), the XUV Photometer System (XPS), and
the Total Irradiance Monitor (TIM) instruments on the Solar Radiation
and Climate Experiment (SORCE) spacecraft took daily solar spectral
irradiance (SSI) and total solar irradiance (TSI) measurements since
April and February 2003, respectively. The SORCE was decommissioned
on February 25, 2020 at which time the SORCE mission began its final
mission phase (Phase-F). All final data products and documents,
as well as all selected ancillary information, have been organized
in compliance with NASA's Earth Science Data Preservation Content
Specification (423-SPEC-001), archived at the NASA Goddard Earth
Sciences Data and Information Services Center (GES DISC), and made
available to the public. We describe the data, documentation, and the
various formats that have been selected for archival.
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Title: Evidence for Top Quark Production in Nucleus-Nucleus Collisions
Authors: Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Ambrogi, F.;
Bergauer, T.; Dragicevic, M.; Erö, J.; Escalante Del Valle, A.;
Frühwirth, R.; Jeitler, M.; Krammer, N.; Lechner, L.; Liko, D.;
Madlener, T.; Mikulec, I.; Rad, N.; Schieck, J.; Schöfbeck, R.;
Spanring, M.; Templ, S.; Waltenberger, W.; Wulz, C. -E.; Zarucki,
M.; Chekhovsky, V.; Litomin, A.; Makarenko, V.; Suarez Gonzalez, J.;
Darwish, M. R.; De Wolf, E. A.; Di Croce, D.; Janssen, X.; Kello,
T.; Lelek, A.; Pieters, M.; Rejeb Sfar, H.; Van Haevermaet, H.; Van
Mechelen, P.; Van Putte, S.; Van Remortel, N.; Blekman, F.; Bols,
E. S.; Chhibra, S. S.; D'Hondt, J.; De Clercq, J.; Lontkovskyi, D.;
Lowette, S.; Marchesini, I.; Moortgat, S.; Python, Q.; Tavernier, S.;
Van Doninck, W.; Van Mulders, P.; Beghin, D.; Bilin, B.; Clerbaux, B.;
De Lentdecker, G.; Delannoy, H.; Dorney, B.; Favart, L.; Grebenyuk,
A.; Kalsi, A. K.; Makarenko, I.; Moureaux, L.; Pétré, L.; Popov,
A.; Postiau, N.; Starling, E.; Thomas, L.; Vander Velde, C.; Vanlaer,
P.; Vannerom, D.; Wezenbeek, L.; Cornelis, T.; Dobur, D.; Khvastunov,
I.; Niedziela, M.; Roskas, C.; Skovpen, K.; Tytgat, M.; Verbeke, W.;
Vermassen, B.; Vit, M.; Bruno, G.; Bury, F.; Caputo, C.; David, P.;
Delaere, C.; Delcourt, M.; Donertas, I. S.; Giammanco, A.; Lemaitre,
V.; Prisciandaro, J.; Saggio, A.; Taliercio, A.; Teklishyn, M.;
Vischia, P.; Wuyckens, S.; Zobec, J.; Alves, G. A.; Correia Silva,
G.; Hensel, C.; Moraes, A.; Aldá Júnior, W. L.; Belchior Batista
Das Chagas, E.; Carvalho, W.; Chinellato, J.; Coelho, E.; Da Costa,
E. M.; Da Silveira, G. G.; De Jesus Damiao, D.; Fonseca De Souza, S.;
Malbouisson, H.; Martins, J.; Matos Figueiredo, D.; Medina Jaime, M.;
Melo De Almeida, M.; Mora Herrera, C.; Mundim, L.; Nogima, H.; Rebello
Teles, P.; Sanchez Rosas, L. J.; Santoro, A.; Silva Do Amaral, S. M.;
Sznajder, A.; Thiel, M.; Tonelli Manganote, E. J.; Torres Da Silva
De Araujo, F.; Vilela Pereira, A.; Bernardes, C. A.; Calligaris,
L.; Fernandez Perez Tomei, T. R.; Gregores, E. M.; Lemos, D. S.;
Mercadante, P. G.; Novaes, S. F.; Padula, Sandra S.; Aleksandrov, A.;
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Messineo, A.; Palla, F.; Rizzi, A.; Rolandi, G.; Roy Chowdhury, S.;
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Turini, N.; Venturi, A.; Verdini, P. G.; Cavallari, F.; Cipriani,
M.; Del Re, D.; Di Marco, E.; Diemoz, M.; Longo, E.; Meridiani, P.;
Organtini, G.; Pandolfi, F.; Paramatti, R.; Quaranta, C.; Rahatlou, S.;
Rovelli, C.; Santanastasio, F.; Soffi, L.; Tramontano, R.; Amapane,
N.; Arcidiacono, R.; Argiro, S.; Arneodo, M.; Bartosik, N.; Bellan,
R.; Bellora, A.; Biino, C.; Cappati, A.; Cartiglia, N.; Cometti, S.;
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C.; Maselli, S.; Migliore, E.; Monaco, V.; Monteil, E.; Monteno, M.;
Obertino, M. M.; Ortona, G.; Pacher, L.; Pastrone, N.; Pelliccioni,
M.; Pinna Angioni, G. L.; Ruspa, M.; Salvatico, R.; Siviero, F.; Sola,
V.; Solano, A.; Soldi, D.; Staiano, A.; Trocino, D.; Belforte, S.;
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G.; Vazzoler, F.; Dogra, S.; Huh, C.; Kim, B.; Kim, D. H.; Kim, G. N.;
Lee, J.; Lee, S. W.; Moon, C. S.; Oh, Y. D.; Pak, S. I.; Sekmen, S.;
Yang, Y. C.; Kim, H.; Moon, D. H.; Francois, B.; Kim, T. J.; Park,
J.; Cho, S.; Choi, S.; Go, Y.; Ha, S.; Hong, B.; Lee, K.; Lee, K. S.;
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S.; Kim, J.; Kim, J. S.; Ko, S.; Kwon, H.; Lee, H.; Lee, K.; Lee, S.;
Nam, K.; Oh, B. H.; Oh, M.; Oh, S. B.; Radburn-Smith, B. C.; Seo, H.;
Yang, U. K.; Yoon, I.; Jeon, D.; Kim, J. H.; Ko, B.; Lee, J. S. H.;
Park, I. C.; Watson, I. J.; Yoo, H. D.; Choi, Y.; Hwang, C.; Jeong,
Y.; Lee, H.; Lee, J.; Lee, Y.; Yu, I.; Veckalns, V.; Juodagalvis, A.;
Rinkevicius, A.; Tamulaitis, G.; Wan Abdullah, W. A. T.; Yusli, M. N.;
Zolkapli, Z.; Benitez, J. F.; Castaneda Hernandez, A.; Murillo Quijada,
J. A.; Valencia Palomo, L.; Castilla-Valdez, H.; De La Cruz-Burelo,
E.; Heredia-De La Cruz, I.; Lopez-Fernandez, R.; Sanchez-Hernandez,
A.; Carrillo Moreno, S.; Oropeza Barrera, C.; Ramirez-Garcia, M.;
Vazquez Valencia, F.; Eysermans, J.; Pedraza, I.; Salazar Ibarguen,
H. A.; Uribe Estrada, C.; Morelos Pineda, A.; Mijuskovic, J.; Raicevic,
N.; Krofcheck, D.; Bheesette, S.; Butler, P. H.; Ahmad, A.; Asghar,
M. I.; Awan, M. I. M.; Hassan, Q.; Hoorani, H. R.; Khan, W. A.; Shah,
M. A.; Shoaib, M.; Waqas, M.; Avati, V.; Grzanka, L.; Malawski, M.;
Bialkowska, H.; Bluj, M.; Boimska, B.; Frueboes, T.; Górski, M.;
Kazana, M.; Szleper, M.; Traczyk, P.; Zalewski, P.; Bunkowski, K.;
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J.; Olszewski, M.; Walczak, M.; Araujo, M.; Bargassa, P.; Bastos, D.;
Di Francesco, A.; Faccioli, P.; Galinhas, B.; Gallinaro, M.; Hollar,
J.; Leonardo, N.; Niknejad, T.; Seixas, J.; Shchelina, K.; Toldaiev,
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I.; Gorbounov, N.; Gorbunov, I.; Kamenev, A.; Karjavine, V.; Korenkov,
V.; Lanev, A.; Malakhov, A.; Matveev, V.; Moisenz, P.; Palichik, V.;
Perelygin, V.; Seitova, D.; Shmatov, S.; Smirnov, V.; Teryaev, O.;
Voytishin, N.; Zarubin, A.; Gavrilov, G.; Golovtcov, V.; Ivanov, Y.;
Kim, V.; Kuznetsova, E.; Murzin, V.; Oreshkin, V.; Smirnov, I.; Sosnov,
D.; Sulimov, V.; Uvarov, L.; Volkov, S.; Vorobyev, A.; Andreev, Yu.;
Dermenev, A.; Gninenko, S.; Golubev, N.; Karneyeu, A.; Kirsanov, M.;
Krasnikov, N.; Pashenkov, A.; Pivovarov, G.; Tlisov, D.; Toropin, A.;
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V.; Pozdnyakov, I.; Safronov, G.; Spiridonov, A.; Stepennov, A.;
Toms, M.; Vlasov, E.; Zhokin, A.; Aushev, T.; Chistov, R.; Danilov,
M.; Parygin, P.; Philippov, D.; Polikarpov, S.; Andreev, V.; Azarkin,
M.; Dremin, I.; Kirakosyan, M.; Terkulov, A.; Baskakov, A.; Belyaev,
A.; Boos, E.; Dudko, L.; Ershov, A.; Gribushin, A.; Kodolova, O.;
Korotkikh, V.; Lokhtin, I.; Obraztsov, S.; Petrushanko, S.; Savrin,
V.; Snigirev, A.; Blinov, V.; Dimova, T.; Kardapoltsev, L.; Ovtin,
I.; Skovpen, Y.; Azhgirey, I.; Bayshev, I.; Kachanov, V.; Kalinin,
A.; Konstantinov, D.; Petrov, V.; Ryutin, R.; Sobol, A.; Troshin,
S.; Tyurin, N.; Uzunian, A.; Volkov, A.; Babaev, A.; Iuzhakov, A.;
Okhotnikov, V.; Borchsh, V.; Ivanchenko, V.; Tcherniaev, E.; Adzic, P.;
Cirkovic, P.; Dordevic, M.; Milenovic, P.; Milosevic, J.; Stojanovic,
M.; Aguilar-Benitez, M.; Alcaraz Maestre, J.; Álvarez Fernández, A.;
Bachiller, I.; Barrio Luna, M.; Brochero Cifuentes, J. A.; Carrillo
Montoya, C. A.; Cepeda, M.; Cerrada, M.; Colino, N.; De La Cruz, B.;
Delgado Peris, A.; Fernandez Bedoya, C.; Fernández Ramos, J. P.; Flix,
J.; Fouz, M. C.; Gonzalez Lopez, O.; Goy Lopez, S.; Hernandez, J. M.;
Josa, M. I.; Moran, D.; Navarro Tobar, Á.; Pérez-Calero Yzquierdo,
A.; Puerta Pelayo, J.; Redondo, I.; Romero, L.; Sánchez Navas, S.;
Soares, M. S.; Triossi, A.; Willmott, C.; Albajar, C.; de Trocóniz,
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Palencia Cortezon, E.; Ramón Álvarez, C.; Rodríguez Bouza, V.;
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Duarte Campderros, J.; Fernandez, M.; Fernández Manteca, P. J.;
García Alonso, A.; Gomez, G.; Martinez Rivero, C.; Martinez Ruiz del
Arbol, P.; Matorras, F.; Piedra Gomez, J.; Prieels, C.; Ricci-Tam,
F.; Rodrigo, T.; Ruiz-Jimeno, A.; Russo, L.; Scodellaro, L.; Vila,
I.; Vizan Garcia, J. M.; Jayananda, MK; Kailasapathy, B.; Sonnadara,
D. U. J.; Wickramarathna, DDC; Dharmaratna, W. G. D.; Liyanage, K.;
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Auffray, E.; Auzinger, G.; Baechler, J.; Baillon, P.; Ball, A. H.;
Barney, D.; Bendavid, J.; Bianco, M.; Bocci, A.; Bortignon, P.;
Bossini, E.; Brondolin, E.; Camporesi, T.; Cerminara, G.; Cristella,
L.; d'Enterria, D.; Dabrowski, A.; Daci, N.; Daponte, V.; David, A.;
De Roeck, A.; Deile, M.; Di Maria, R.; Dobson, M.; Dünser, M.; Dupont,
N.; Elliott-Peisert, A.; Emriskova, N.; Fallavollita, F.; Fasanella,
D.; Fiorendi, S.; Franzoni, G.; Fulcher, J.; Funk, W.; Giani, S.;
Gigi, D.; Gill, K.; Glege, F.; Gouskos, L.; Gruchala, M.; Guilbaud,
M.; Gulhan, D.; Hegeman, J.; Iiyama, Y.; Innocente, V.; James, T.;
Janot, P.; Kaspar, J.; Kieseler, J.; Komm, M.; Kratochwil, N.; Lange,
C.; Lecoq, P.; Long, K.; Lourenço, C.; Malgeri, L.; Mannelli, M.;
Massironi, A.; Meijers, F.; Mersi, S.; Meschi, E.; Moortgat, F.;
Mulders, M.; Ngadiuba, J.; Niedziela, J.; Orfanelli, S.; Orsini,
L.; Pantaleo, F.; Pape, L.; Perez, E.; Peruzzi, M.; Petrilli, A.;
Petrucciani, G.; Pfeiffer, A.; Pierini, M.; Pitters, F. M.; Rabady,
D.; Racz, A.; Rieger, M.; Rovere, M.; Sakulin, H.; Salfeld-Nebgen,
J.; Scarfi, S.; Schäfer, C.; Schwick, C.; Selvaggi, M.; Sharma,
A.; Silva, P.; Snoeys, W.; Sphicas, P.; Steggemann, J.; Summers, S.;
Tavolaro, V. R.; Treille, D.; Tsirou, A.; Van Onsem, G. P.; Vartak, A.;
Verzetti, M.; Wozniak, K. A.; Zeuner, W. D.; Caminada, L.; Erdmann,
W.; Horisberger, R.; Ingram, Q.; Kaestli, H. C.; Kotlinski, D.;
Langenegger, U.; Rohe, T.; Backhaus, M.; Berger, P.; Calandri, A.;
Chernyavskaya, N.; Dissertori, G.; Dittmar, M.; Donegà, M.; Dorfer,
C.; Gadek, T.; Gómez Espinosa, T. A.; Grab, C.; Hits, D.; Lustermann,
W.; Lyon, A. -M.; Manzoni, R. A.; Meinhard, M. T.; Micheli, F.;
Musella, P.; Nessi-Tedaldi, F.; Pauss, F.; Perovic, V.; Perrin, G.;
Perrozzi, L.; Pigazzini, S.; Ratti, M. G.; Reichmann, M.; Reissel,
C.; Reitenspiess, T.; Ristic, B.; Ruini, D.; Sanz Becerra, D. A.;
Schönenberger, M.; Shchutska, L.; Stampf, V.; Vesterbacka Olsson,
M. L.; Wallny, R.; Zhu, D. H.; Amsler, C.; Botta, C.; Brzhechko,
D.; Canelli, M. F.; De Cosa, A.; Del Burgo, R.; Heikkilä, J. K.;
Huwiler, M.; Jofrehei, A.; Kilminster, B.; Leontsinis, S.; Macchiolo,
A.; Mikuni, V. M.; Molinatti, U.; Neutelings, I.; Rauco, G.; Robmann,
P.; Schweiger, K.; Takahashi, Y.; Wertz, S.; Adloff, C.; Kuo, C. M.;
Lin, W.; Roy, A.; Sarkar, T.; Yu, S. S.; Ceard, L.; Chang, P.; Chao,
Y.; Chen, K. F.; Chen, P. H.; Hou, W. -S.; Li, Y. y.; Lu, R. -S.;
Paganis, E.; Psallidas, A.; Steen, A.; Yazgan, E.; Asavapibhop, B.;
Asawatangtrakuldee, C.; Srimanobhas, N.; Boran, F.; Damarseckin,
S.; Demiroglu, Z. S.; Dolek, F.; Dozen, C.; Dumanoglu, I.; Eskut, E.;
Gokbulut, G.; Guler, Y.; Gurpinar Guler, E.; Hos, I.; Isik, C.; Kangal,
E. E.; Kara, O.; Kayis Topaksu, A.; Kiminsu, U.; Onengut, G.; Ozdemir,
K.; Polatoz, A.; Simsek, A. E.; Tali, B.; Tok, U. G.; Turkcapar, S.;
Zorbakir, I. S.; Zorbilmez, C.; Isildak, B.; Karapinar, G.; Ocalan, K.;
Yalvac, M.; Atakisi, I. O.; Gülmez, E.; Kaya, M.; Kaya, O.; Özçelik,
Ö.; Tekten, S.; Yetkin, E. A.; Cakir, A.; Cankocak, K.; Komurcu,
Y.; Sen, S.; Aydogmus Sen, F.; Cerci, S.; Kaynak, B.; Ozkorucuklu,
S.; Sunar Cerci, D.; Grynyov, B.; Levchuk, L.; Bhal, E.; Bologna,
S.; Brooke, J. J.; Burns, D.; Clement, E.; Cussans, D.; Flacher, H.;
Goldstein, J.; Heath, G. P.; Heath, H. F.; Kreczko, L.; Krikler, B.;
Paramesvaran, S.; Sakuma, T.; Seif El Nasr-Storey, S.; Smith, V. J.;
Taylor, J.; Titterton, A.; Bell, K. W.; Belyaev, A.; Brew, C.; Brown,
R. M.; Cockerill, D. J. A.; Ellis, K. V.; Harder, K.; Harper, S.;
Linacre, J.; Manolopoulos, K.; Newbold, D. M.; Olaiya, E.; Petyt,
D.; Reis, T.; Schuh, T.; Shepherd-Themistocleous, C. H.; Thea, A.;
Tomalin, I. R.; Williams, T.; Bainbridge, R.; Bloch, P.; Bonomally,
S.; Borg, J.; Breeze, S.; Buchmuller, O.; Bundock, A.; Cepaitis, V.;
Chahal, G. S.; Colling, D.; Dauncey, P.; Davies, G.; Della Negra, M.;
Everaerts, P.; Fedi, G.; Hall, G.; Iles, G.; Langford, J.; Lyons, L.;
Magnan, A. -M.; Malik, S.; Martelli, A.; Milosevic, V.; Morton, A.;
Nash, J.; Palladino, V.; Pesaresi, M.; Raymond, D. M.; Richards, A.;
Rose, A.; Scott, E.; Seez, C.; Shtipliyski, A.; Stoye, M.; Tapper,
A.; Uchida, K.; Virdee, T.; Wardle, N.; Webb, S. N.; Winterbottom,
D.; Zecchinelli, A. G.; Zenz, S. C.; Cole, J. E.; Hobson, P. R.;
Khan, A.; Kyberd, P.; Mackay, C. K.; Reid, I. D.; Teodorescu, L.;
Zahid, S.; Brinkerhoff, A.; Call, K.; Caraway, B.; Dittmann, J.;
Hatakeyama, K.; Madrid, C.; McMaster, B.; Pastika, N.; Smith, C.;
Bartek, R.; Dominguez, A.; Uniyal, R.; Vargas Hernandez, A. M.;
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C.; Rumerio, P.; West, C.; Akpinar, A.; Albert, A.; Arcaro, D.;
Cosby, C.; Demiragli, Z.; Gastler, D.; Richardson, C.; Rohlf, J.;
Salyer, K.; Sperka, D.; Spitzbart, D.; Suarez, I.; Yuan, S.; Zou, D.;
Benelli, G.; Burkle, B.; Coubez, X.; Cutts, D.; Duh, Y. t.; Hadley,
M.; Heintz, U.; Hogan, J. M.; Kwok, K. H. M.; Laird, E.; Landsberg,
G.; Lau, K. T.; Lee, J.; Narain, M.; Sagir, S.; Syarif, R.; Usai, E.;
Wong, W. Y.; Yu, D.; Zhang, W.; Band, R.; Brainerd, C.; Breedon, R.;
Calderon De La Barca Sanchez, M.; Chertok, M.; Conway, J.; Conway,
R.; Cox, P. T.; Erbacher, R.; Flores, C.; Funk, G.; Jensen, F.; Ko,
W.; Kukral, O.; Lander, R.; Mulhearn, M.; Pellett, D.; Pilot, J.; Shi,
M.; Taylor, D.; Tos, K.; Tripathi, M.; Yao, Y.; Zhang, F.; Bachtis,
M.; Bravo, C.; Cousins, R.; Dasgupta, A.; Florent, A.; Hamilton, D.;
Hauser, J.; Ignatenko, M.; Lam, T.; Mccoll, N.; Nash, W. A.; Regnard,
S.; Saltzberg, D.; Schnaible, C.; Stone, B.; Valuev, V.; Burt, K.;
Chen, Y.; Clare, R.; Gary, J. W.; Ghiasi Shirazi, S. M. A.; Hanson,
G.; Karapostoli, G.; Long, O. R.; Manganelli, N.; Olmedo Negrete, M.;
Paneva, M. I.; Si, W.; Wimpenny, S.; Zhang, Y.; Branson, J. G.; Chang,
P.; Cittolin, S.; Cooperstein, S.; Deelen, N.; Derdzinski, M.; Duarte,
J.; Gerosa, R.; Gilbert, D.; Hashemi, B.; Klein, D.; Krutelyov, V.;
Letts, J.; Masciovecchio, M.; May, S.; Padhi, S.; Pieri, M.; Sharma,
V.; Tadel, M.; Würthwein, F.; Yagil, A.; Amin, N.; Bhandari, R.;
Campagnari, C.; Citron, M.; Dorsett, A.; Dutta, V.; Incandela, J.;
Marsh, B.; Mei, H.; Ovcharova, A.; Qu, H.; Quinnan, M.; Richman, J.;
Sarica, U.; Stuart, D.; Wang, S.; Anderson, D.; Bornheim, A.; Cerri,
O.; Dutta, I.; Lawhorn, J. M.; Lu, N.; Mao, J.; Newman, H. B.; Nguyen,
T. Q.; Pata, J.; Spiropulu, M.; Vlimant, J. R.; Xie, S.; Zhang, Z.;
Zhu, R. Y.; Alison, J.; Andrews, M. B.; Ferguson, T.; Mudholkar, T.;
Paulini, M.; Sun, M.; Vorobiev, I.; Weinberg, M.; Cumalat, J. P.;
Ford, W. T.; MacDonald, E.; Mulholland, T.; Patel, R.; Perloff, A.;
Stenson, K.; Ulmer, K. A.; Wagner, S. R.; Alexander, J.; Cheng, Y.;
Chu, J.; Cranshaw, D. J.; Datta, A.; Frankenthal, A.; Mcdermott, K.;
Monroy, J.; Patterson, J. R.; Quach, D.; Ryd, A.; Sun, W.; Tan, S. M.;
Tao, Z.; Thom, J.; Wittich, P.; Zientek, M.; Abdullin, S.; Albrow,
M.; Alyari, M.; Apollinari, G.; Apresyan, A.; Apyan, A.; Banerjee,
S.; Bauerdick, L. A. T.; Beretvas, A.; Berry, D.; Berryhill, J.;
Bhat, P. C.; Burkett, K.; Butler, J. N.; Canepa, A.; Cerati, G. B.;
Cheung, H. W. K.; Chlebana, F.; Cremonesi, M.; Elvira, V. D.; Freeman,
J.; Gecse, Z.; Gottschalk, E.; Gray, L.; Green, D.; Grünendahl,
S.; Gutsche, O.; Harris, R. M.; Hasegawa, S.; Heller, R.; Herwig,
T. C.; Hirschauer, J.; Jayatilaka, B.; Jindariani, S.; Johnson, M.;
Joshi, U.; Klijnsma, T.; Klima, B.; Kortelainen, M. J.; Lammel, S.;
Lewis, J.; Lincoln, D.; Lipton, R.; Liu, M.; Liu, T.; Lykken, J.;
Maeshima, K.; Mason, D.; McBride, P.; Merkel, P.; Mrenna, S.; Nahn,
S.; O'Dell, V.; Papadimitriou, V.; Pedro, K.; Pena, C.; Prokofyev,
O.; Ravera, F.; Reinsvold Hall, A.; Ristori, L.; Schneider, B.;
Sexton-Kennedy, E.; Smith, N.; Soha, A.; Spalding, W. J.; Spiegel,
L.; Stoynev, S.; Strait, J.; Taylor, L.; Tkaczyk, S.; Tran, N. V.;
Uplegger, L.; Vaandering, E. W.; Wang, M.; Weber, H. A.; Woodard,
A.; Acosta, D.; Avery, P.; Bourilkov, D.; Cadamuro, L.; Cherepanov,
V.; Errico, F.; Field, R. D.; Guerrero, D.; Joshi, B. M.; Kim, M.;
Konigsberg, J.; Korytov, A.; Lo, K. H.; Matchev, K.; Menendez, N.;
Mitselmakher, G.; Rosenzweig, D.; Shi, K.; Wang, J.; Wang, S.; Zuo,
X.; Joshi, Y. R.; Adams, T.; Askew, A.; Diaz, D.; Habibullah, R.;
Hagopian, S.; Hagopian, V.; Johnson, K. F.; Khurana, R.; Kolberg,
T.; Martinez, G.; Prosper, H.; Schiber, C.; Yohay, R.; Zhang, J.;
Baarmand, M. M.; Butalla, S.; Elkafrawy, T.; Hohlmann, M.; Noonan, D.;
Rahmani, M.; Saunders, M.; Yumiceva, F.; Adams, M. R.; Apanasevich,
L.; Becerril Gonzalez, H.; Cavanaugh, R.; Chen, X.; Dittmer, S.;
Evdokimov, O.; Gerber, C. E.; Hangal, D. A.; Hofman, D. J.; Mills, C.;
Oh, G.; Roy, T.; Tonjes, M. B.; Varelas, N.; Viinikainen, J.; Wang,
H.; Wang, X.; Wu, Z.; Alhusseini, M.; Bilki, B.; Dilsiz, K.; Durgut,
S.; Gandrajula, R. P.; Haytmyradov, M.; Khristenko, V.; Köseyan,
O. K.; Merlo, J. -P.; Mestvirishvili, A.; Moeller, A.; Nachtman,
J.; Ogul, H.; Onel, Y.; Ozok, F.; Penzo, A.; Snyder, C.; Tiras,
E.; Wetzel, J.; Yi, K.; Amram, O.; Blumenfeld, B.; Corcodilos, L.;
Eminizer, M.; Gritsan, A. V.; Kyriacou, S.; Maksimovic, P.; Mantilla,
C.; Roskes, J.; Swartz, M.; Vámi, T. Á.; Baldenegro Barrera, C.;
Baringer, P.; Bean, A.; Bylinkin, A.; Isidori, T.; Khalil, S.; King,
J.; Krintiras, G.; Kropivnitskaya, A.; Lindsey, C.; Mcbrayer, W.;
Minafra, N.; Murray, M.; Rogan, C.; Royon, C.; Sanders, S.; Schmitz,
E.; Tapia Takaki, J. D.; Wang, Q.; Williams, J.; Wilson, G.; Duric,
S.; Ivanov, A.; Kaadze, K.; Kim, D.; Maravin, Y.; Mendis, D. R.;
Mitchell, T.; Modak, A.; Mohammadi, A.; Rebassoo, F.; Wright, D.;
Adams, E.; Baden, A.; Baron, O.; Belloni, A.; Eno, S. C.; Feng, Y.;
Hadley, N. J.; Jabeen, S.; Jeng, G. Y.; Kellogg, R. G.; Koeth, T.;
Mignerey, A. C.; Nabili, S.; Seidel, M.; Skuja, A.; Tonwar, S. C.;
Wang, L.; Wong, K.; Abercrombie, D.; Allen, B.; Bi, R.; Brandt, S.;
Busza, W.; Cali, I. A.; Chen, Y.; D'Alfonso, M.; Gomez Ceballos, G.;
Goncharov, M.; Harris, P.; Hsu, D.; Hu, M.; Klute, M.; Kovalskyi,
D.; Krupa, J.; Lee, Y. -J.; Luckey, P. D.; Maier, B.; Marini, A. C.;
Mcginn, C.; Mironov, C.; Narayanan, S.; Niu, X.; Paus, C.; Rankin,
D.; Roland, C.; Roland, G.; Shi, Z.; Stephans, G. S. F.; Sumorok, K.;
Tatar, K.; Velicanu, D.; Wang, J.; Wang, T. W.; Wang, Z.; Wyslouch,
B.; Chatterjee, R. M.; Evans, A.; Guts, S.; Hansen, P.; Hiltbrand, J.;
Jain, Sh.; Krohn, M.; Kubota, Y.; Lesko, Z.; Mans, J.; Revering, M.;
Rusack, R.; Saradhy, R.; Schroeder, N.; Strobbe, N.; Wadud, M. A.;
Acosta, J. G.; Oliveros, S.; Bloom, K.; Chauhan, S.; Claes, D. R.;
Fangmeier, C.; Finco, L.; Golf, F.; González Fernández, J. R.;
Kravchenko, I.; Siado, J. E.; Snow, G. R.; Stieger, B.; Tabb, W.;
Agarwal, G.; Harrington, C.; Iashvili, I.; Kharchilava, A.; McLean,
C.; Nguyen, D.; Parker, A.; Pekkanen, J.; Rappoccio, S.; Roozbahani,
B.; Alverson, G.; Barberis, E.; Freer, C.; Haddad, Y.; Hortiangtham,
A.; Madigan, G.; Marzocchi, B.; Morse, D. M.; Nguyen, V.; Orimoto,
T.; Skinnari, L.; Tishelman-Charny, A.; Wamorkar, T.; Wang, B.;
Wisecarver, A.; Wood, D.; Bhattacharya, S.; Bueghly, J.; Chen, Z.;
Gilbert, A.; Gunter, T.; Hahn, K. A.; Odell, N.; Schmitt, M. H.;
Sung, K.; Velasco, M.; Bucci, R.; Dev, N.; Goldouzian, R.; Hildreth,
M.; Hurtado Anampa, K.; Jessop, C.; Karmgard, D. J.; Lannon, K.;
Li, W.; Loukas, N.; Marinelli, N.; Mcalister, I.; Meng, F.; Mohrman,
K.; Musienko, Y.; Ruchti, R.; Siddireddy, P.; Taroni, S.; Wayne, M.;
Wightman, A.; Wolf, M.; Zygala, L.; Alimena, J.; Bylsma, B.; Cardwell,
B.; Durkin, L. S.; Francis, B.; Hill, C.; Ji, W.; Lefeld, A.; Winer,
B. L.; Yates, B. R.; Dezoort, G.; Elmer, P.; Greenberg, B.; Haubrich,
N.; Higginbotham, S.; Kalogeropoulos, A.; Kopp, G.; Kwan, S.; Lange,
D.; Lucchini, M. T.; Luo, J.; Marlow, D.; Mei, K.; Ojalvo, I.; Olsen,
J.; Palmer, C.; Piroué, P.; Stickland, D.; Tully, C.; Malik, S.;
Norberg, S.; Barnes, V. E.; Chawla, R.; Das, S.; Gutay, L.; Jones,
M.; Jung, A. W.; Mahakud, B.; Negro, G.; Neumeister, N.; Peng, C. C.;
Piperov, S.; Qiu, H.; Schulte, J. F.; Trevisani, N.; Wang, F.; Xiao,
R.; Xie, W.; Cheng, T.; Dolen, J.; Parashar, N.; Baty, A.; Dildick, S.;
Ecklund, K. M.; Freed, S.; Geurts, F. J. M.; Kilpatrick, M.; Kumar,
A.; Li, W.; Padley, B. P.; Redjimi, R.; Roberts, J.; Rorie, J.; Shi,
W.; Stahl Leiton, A. G.; Tu, Z.; Zhang, A.; Bodek, A.; de Barbaro,
P.; Demina, R.; Dulemba, J. L.; Fallon, C.; Ferbel, T.; Galanti,
M.; Garcia-Bellido, A.; Hindrichs, O.; Khukhunaishvili, A.; Ranken,
E.; Taus, R.; Chiarito, B.; Chou, J. P.; Gandrakota, A.; Gershtein,
Y.; Halkiadakis, E.; Hart, A.; Heindl, M.; Hughes, E.; Kaplan, S.;
Karacheban, O.; Laflotte, I.; Lath, A.; Montalvo, R.; Nash, K.;
Osherson, M.; Salur, S.; Schnetzer, S.; Somalwar, S.; Stone, R.;
Thayil, S. A.; Thomas, S.; Acharya, H.; Delannoy, A. G.; Spanier,
S.; Bouhali, O.; Dalchenko, M.; Delgado, A.; Eusebi, R.; Gilmore,
J.; Huang, T.; Kamon, T.; Kim, H.; Luo, S.; Malhotra, S.; Marley,
D.; Mueller, R.; Overton, D.; Perniè, L.; Rathjens, D.; Safonov, A.;
Akchurin, N.; Damgov, J.; Hegde, V.; Kunori, S.; Lamichhane, K.; Lee,
S. W.; Mengke, T.; Muthumuni, S.; Peltola, T.; Undleeb, S.; Volobouev,
I.; Wang, Z.; Whitbeck, A.; Appelt, E.; Greene, S.; Gurrola, A.;
Janjam, R.; Johns, W.; Maguire, C.; Melo, A.; Ni, H.; Padeken, K.;
Romeo, F.; Sheldon, P.; Tuo, S.; Velkovska, J.; Verweij, M.; Ang, L.;
Arenton, M. W.; Cox, B.; Cummings, G.; Hakala, J.; Hirosky, R.; Joyce,
M.; Ledovskoy, A.; Neu, C.; Tannenwald, B.; Wang, Y.; Wolfe, E.; Xia,
F.; Karchin, P. E.; Poudyal, N.; Sturdy, J.; Thapa, P.; Black, K.;
Bose, T.; Buchanan, J.; Caillol, C.; Dasu, S.; De Bruyn, I.; Dodd, L.;
Galloni, C.; He, H.; Herndon, M.; Hervé, A.; Hussain, U.; Lanaro, A.;
Loeliger, A.; Loveless, R.; Madhusudanan Sreekala, J.; Mallampalli,
A.; Pinna, D.; Ruggles, T.; Savin, A.; Shang, V.; Sharma, V.; Smith,
W. H.; Teague, D.; Trembath-reichert, S.; Vetens, W.; CMS Collaboration
2020PhRvL.125v2001S Altcode:
Ultrarelativistic heavy ion collisions recreate in the laboratory
the thermodynamical conditions prevailing in the early universe up to
10<SUP>-6</SUP> sec , thereby allowing the study of the quark-gluon
plasma (QGP), a state of quantum chromodynamics (QCD) matter with
deconfined partons. The top quark, the heaviest elementary particle
known, is accessible in nucleus-nucleus collisions at the CERN
LHC, and constitutes a novel probe of the QGP. Here, we report the
first evidence for the production of top quarks in nucleus-nucleus
collisions, using lead-lead collision data at a nucleon-nucleon
center-of-mass energy of 5.02 TeV recorded by the CMS experiment. Two
methods are used to measure the cross section for top quark pair
production (σ<SUB>t t ¯</SUB> ) via the selection of charged
leptons (electrons or muons) and bottom quarks. One method relies
on the leptonic information alone, and the second one exploits,
in addition, the presence of bottom quarks. The measured cross
sections, σ<SUB>t t ¯</SUB>=2.5 4<SUB>-0.74</SUB><SUP>+0.84</SUP> and
2.03<SUB>-0.64</SUB><SUP>+0.71</SUP> μ b , respectively, are compatible
with expectations from scaled proton-proton data and QCD predictions.
---------------------------------------------------------
Title: VizieR Online Data Catalog: Faculae-Spot dominance &
rotation periods (Amazo-Gomez+, 2020)
Authors: Amazo-Gomez, E. M.; Shapiro, A. I.; Solanki, S. K.; Kopp,
G.; Oshagh, M.; Reinhold, T.; Reiners, A.
2020yCat..36420225A Altcode:
This table contains an example of the GPS outputs, the compared
rotation period values from GLS and ACF, and stellar parameters for
Kepler stars. <P />In column 4 and 5 values of alpha-factor and its
2-sigma uncertainty are reported respectively. Prot GPS values in
column 6, as result of applying Eq. 1 using the factor alpha=0.19. 2)
Column 7 shows the Prot reported by Reinhold & Gizon (2015,
Cat. J/A+A/583/A65). 3) Prot and variability values reported by
McQuillan et al. (2014, Cat. J/ApJS/211/24) in column 8. 4) Columns
10, 11 and 12 show the logg, [Fe/H], and Teff respectively, taken from
Huber et al. (2014, Cat J/ApJS/211/2). <P />(1 data file).
---------------------------------------------------------
Title: Inflection point in the power spectrum of stellar brightness
variations. III. Facular versus spot dominance on stars with known
rotation periods
Authors: Amazo-Gómez, E. M.; Shapiro, A. I.; Solanki, S. K.; Kopp,
G.; Oshagh, M.; Reinhold, T.; Reiners, A.
2020A&A...642A.225A Altcode: 2020arXiv200811492A
Context. Stellar rotation periods can be determined by observing
brightness variations caused by active magnetic regions transiting
visible stellar disk as the star rotates. Successful stellar photometric
surveys stemming from the Kepler and TESS observations have led to
the determination of rotation periods in tens of thousands of young
and active stars. However, there is still a lack of information on
the rotation periods of older and less active stars like the Sun. The
irregular temporal profiles of light curves caused by the decay times of
active regions, which are comparable to, or even shorter than, stellar
rotation periods, in combination with the random emergence of active
regions make period determination for such stars very difficult. <BR />
Aims: We tested the performance of a new method for the determination
of stellar rotation periods against stars with previously determined
rotation periods. The method is based on calculating the gradient of the
power spectrum (GPS) and identifying the position of the inflection
point (i.e. point with the highest gradient). The GPS method is
specifically aimed at determining rotation periods of low-activity
stars like the Sun. <BR /> Methods: We applied the GPS method to 1047
Sun-like stars observed by the Kepler telescope. We considered two
stellar samples individually: one with near-solar rotation periods
(24-27.4 d) and a broad range of effective temperatures (5000-6000 K)
and the other with near-solar effective temperatures (5700-5900 K)
and a broad range of rotation periods (15-40 d). <BR /> Results: We
show that the GPS method returns precise values for stellar rotation
periods. Furthermore, it allows us to constrain the ratio between
facular and spot areas of active regions at the moment of their
emergence. We also show that the relative facular area decreases with
the stellar rotation rate. <BR /> Conclusions: Our results suggest
that the GPS method can be successfully applied to retrieve the
periods of stars with both regular and non-regular light curves. <P
/>Full Table 2 is only available at the CDS via anonymous ftp to <A
href="http://cdsarc.u-strasbg.fr">http://cdsarc.u-strasbg.fr</A>
(ftp://130.79.128.5) or via <A
href="http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A225">http://cdsarc.u-strasbg.fr/viz-bin/cat/J/A+A/642/A225</A>
---------------------------------------------------------
Title: Solar Irradiance Variability: Modeling the Measurements
Authors: Lean, J. L.; Coddington, O.; Marchenko, S. V.; Machol, J.;
DeLand, M. T.; Kopp, G.
2020E&SS....700645L Altcode:
New models of the Sun's irradiance variability are developed from 15
years of direct observations made by the Solar Radiation and Climate
Experiment (SORCE) spacecraft from 2003 to 2017 (inclusive). Multiple
linear regression parameterizes the observations in terms of facular
brightening and sunspot darkening, which are the primary sources of
solar irradiance variability. The facular influence is specified as a
combination of a linear and nonlinear solar ultraviolet (UV) index; the
addition of the nonlinear term allows better reproduction of concurrent
solar cycle and rotational variability. The sunspot darkening index is
calculated using sunspot observations from both the Debrecen catalog
and Air Force Solar Observing Optical Network (SOON) operational sites,
the former providing superior model performance. The new model of total
solar irradiance variability, NRLTSI3, with the Debrecen sunspot index
reproduces the direct Total Irradiance Monitor (TIM) observations better
than does the NRLTSI2 model that currently specifies irradiance for
the NOAA Climate Data Record (CDR); the correlation of the model and
observations increases from 0.956 to 0.971, and the standard deviation
of the residuals decreases from 0.124 to 0.100 W m<SUP>-2</SUP>. The
new model of solar spectral irradiance variability, NRLSSI3, which
extends from 115 to 100,000 nm, reproduces rotational modulation in
independent Ozone Monitoring Instrument (OMI) observations at near-UV
and visible wavelengths. The SATIRE model overestimates rotational
modulation of near-UV Fraunhofer spectral features because of excess
facular brightness; the EMPIRE model overestimates rotational modulation
at all near-UV wavelengths.
---------------------------------------------------------
Title: Changing of the Guard for the Total Solar Irradiance Record
Authors: Kopp, Greg; Harber, David; Heuerman, Karl; Stone, Brandon
2020EGUGA..2211489K Altcode:
The uninterrupted, 41-year-long, spaceborne total solar irradiance
(TSI) record has recently undergone several changes in the instruments
contributing to these measurements of the net incoming radiant energy
providing nearly all the power driving the Earth's climate system. Two
long-term instruments, NASA's SORCE/TIM and TCTE/TIM, have recently
been powered off. This ends the 17-year record from the SORCE/TIM,
which established the currently-accepted TSI value of 1361 W m-2 after
its launch in 2003. ESA's SoHO/VIRGO continues to acquire measurements
that extend its 24-year record, but data availability has been on hold
as a new processing methodology is implemented. NASA's recently-launched
TSIS-1/TIM is presently continuing the measurements of these stalwart
legacy instruments. This new TSI instrument is demonstrating higher
on-orbit accuracy than any prior such instrument has achieved,
with daily measurement updates that are available to the community
for climate- and solar-research purposes. I will discuss the many
recent changes to the spaceborne TSI measurement record, the current
measurement-accuracy improvements and stabilities achieved and their
implications for Earth energy-balance studies, and the future plans
to maintain measurement continuity.
---------------------------------------------------------
Title: Inflection point in the power spectrum of stellar brightness
variations. II. The Sun
Authors: Amazo-Gómez, E. M.; Shapiro, A. I.; Solanki, S. K.; Krivova,
N. A.; Kopp, G.; Reinhold, T.; Oshagh, M.; Reiners, A.
2020A&A...636A..69A Altcode: 2020arXiv200203455A
Context. Young and active stars generally have regular, almost
sinusoidal, patterns of variability attributed to their rotation,
while the majority of older and less active stars, including the Sun,
have more complex and non-regular light curves, which do not have clear
rotational-modulation signals. Consequently, the rotation periods have
been successfully determined only for a small fraction of the Sun-like
stars (mainly the active ones) observed by transit-based planet-hunting
missions, such as CoRoT, Kepler, and TESS. This suggests that only
a small fraction of such systems have been properly identified as
solar-like analogues. <BR /> Aims: We aim to apply a new method of
determining rotation periods of low-activity stars, such as the Sun. The
method is based on calculating the gradient of the power spectrum
(GPS) of stellar brightness variations and identifying a tell-tale
inflection point in the spectrum. The rotation frequency is then
proportional to the frequency of that inflection point. In this paper,
we compare this GPS method to already-available photometric records of
the Sun. <BR /> Methods: We applied GPS, auto-correlation functions,
Lomb-Scargle periodograms, and wavelet analyses to the total solar
irradiance (TSI) time series obtained from the Total Irradiance Monitor
on the Solar Radiation and Climate Experiment and the Variability of
solar IRradiance and Gravity Oscillations experiment on the SOlar
and Heliospheric Observatory missions. We analysed the performance
of all methods at various levels of solar activity. <BR /> Results:
We show that the GPS method returns accurate values of solar rotation
independently of the level of solar activity. In particular, it performs
well during periods of high solar activity, when TSI variability
displays an irregular pattern, and other methods fail. Furthermore,
we show that the GPS and light curve skewness can give constraints
on facular and spot contributions to brightness variability. <BR />
Conclusions: Our results suggest that the GPS method can successfully
determine the rotational periods of stars with both regular and
non-regular light curves. <P />The two movies are available at <A
href="https://www.aanda.org/10.1051/0004-6361/201936925/olm">https://www.aanda.org</A>
---------------------------------------------------------
Title: SiPM-matrix readout of two-phase argon detectors using
electroluminescence in the visible and near infrared range
Authors: The DarkSide collaboration; Aalseth, C. E.; Abdelhakim, S.;
Agnes, P.; Ajaj, R.; Albuquerque, I. F. M.; Alexander, T.; Alici, A.;
Alton, A. K.; Amaudruz, P.; Ameli, F.; Anstey, J.; Antonioli, P.; Arba,
M.; Arcelli, S.; Ardito, R.; Arnquist, I. J.; Arpaia, P.; Asner, D. M.;
Asunskis, A.; Ave, M.; Back, H. O.; Barbaryan, V.; Barrado Olmedo,
A.; Batignani, G.; Bisogni, M. G.; Bocci, V.; Bondar, A.; Bonfini,
G.; Bonivento, W.; Borisova, E.; Bottino, B.; Boulay, M. G.; Bunker,
R.; Bussino, S.; Buzulutskov, A.; Cadeddu, M.; Cadoni, M.; Caminata,
A.; Canci, N.; Candela, A.; Cantini, C.; Caravati, M.; Cariello, M.;
Carnesecchi, F.; Castellani, A.; Castello, P.; Cavalcante, P.; Cavazza,
D.; Cavuoti, S.; Cebrian, S.; Cela Ruiz, J. M.; Celano, B.; Cereseto,
R.; Chashin, S.; Cheng, W.; Chepurnov, A.; Cicalò, C.; Cifarelli,
L.; Citterio, M.; Coccetti, F.; Cocco, V.; Colocci, M.; Conde Vilda,
E.; Consiglio, L.; Cossio, F.; Covone, G.; Crivelli, P.; D'Antone,
I.; D'Incecco, M.; Da Rocha Rolo, M. D.; Dadoun, O.; Daniel, M.;
Davini, S.; De Cecco, S.; De Deo, M.; De Falco, A.; De Gruttola, D.;
De Guido, G.; De Rosa, G.; Dellacasa, G.; Demontis, P.; De Pasquale,
S.; Derbin, A. V.; Devoto, A.; Di Eusanio, F.; Di Noto, L.; Di Pietro,
G.; Di Stefano, P.; Dionisi, C.; Dolganov, G.; Dordei, F.; Downing, M.;
Edalatfar, F.; Empl, A.; Fernandez Diaz, M.; Filip, C.; Fiorillo, G.;
Fomenko, K.; Franceschi, A.; Franco, D.; Frolov, E.; Froudakis, G. E.;
Funicello, N.; Gabriele, F.; Gabrieli, A.; Galbiati, C.; Garbini,
M.; Garcia Abia, P.; Gascón Fora, D.; Gendotti, A.; Ghiano, C.;
Ghisi, A.; Giampa, P.; Giampaolo, R. A.; Giganti, C.; Giorgi, M. A.;
Giovanetti, G. K.; Gligan, M. L.; Gorchakov, O.; Grab, M.; Graciani
Diaz, R.; Grassi, M.; Grate, J. W.; Grobov, A.; Gromov, M.; Guan, M.;
Guerra, M. B. B.; Guerzoni, M.; Gulino, M.; Haaland, R. K.; Hackett,
B. R.; Hallin, A.; Haranczyk, M.; Harrop, B.; Hoppe, E. W.; Horikawa,
S.; Hosseini, B.; Hubaut, F.; Humble, P.; Hungerford, E. V.; Ianni,
An.; Ilyasov, A.; Ippolito, V.; Jillings, C.; Keeter, K.; Kendziora,
C. L.; Kochanek, I.; Kondo, K.; Kopp, G.; Korablev, D.; Korga, G.;
Kubankin, A.; Kugathasan, R.; Kuss, M.; La Commara, M.; La Delfa, L.;
Lai, M.; Lebois, M.; Lehnert, B.; Levashko, N.; Li, X.; Liqiang, Q.;
Lissia, M.; Lodi, G. U.; Longo, G.; Lussana, R.; Luzzi, L.; Machado,
A. A.; Machulin, I. N.; Mandarano, A.; Manecki, S.; Mapelli, L.;
Margotti, A.; Mari, S. M.; Mariani, M.; Maricic, J.; Marinelli, M.;
Marras, D.; Martínez, M.; Martinez Rojas, A. D.; Mascia, M.; Mason,
J.; Masoni, A.; McDonald, A. B.; Messina, A.; Miletic, T.; Milincic,
R.; Moggi, A.; Moioli, S.; Monroe, J.; Morrocchi, M.; Mroz, T.; Mu,
W.; Muratova, V. N.; Murphy, S.; Muscas, C.; Musico, P.; Nania, R.;
Napolitano, T.; Navrer Agasson, A.; Nessi, M.; Nikulin, I.; Nosov,
V.; Nowak, J. A.; Oleinik, A.; Oleynikov, V.; Orsini, M.; Ortica,
F.; Pagani, L.; Pallavicini, M.; Palmas, S.; Pandola, L.; Pantic,
E.; Paoloni, E.; Pazzona, F.; Peeters, S.; Pegoraro, P. A.; Pelczar,
K.; Pellegrini, L. A.; Pellegrino, C.; Pelliccia, N.; Perotti, F.;
Pesudo, V.; Picciau, E.; Pietropaolo, F.; Pocar, A.; Pollmann, T. R.;
Portaluppi, D.; Poudel, S. S.; Pralavorio, P.; Price, D.; Radics, B.;
Raffaelli, F.; Ragusa, F.; Razeti, M.; Regenfus, C.; Renshaw, A. L.;
Rescia, S.; Rescigno, M.; Retiere, F.; Rignanese, L. P.; Ripoli, C.;
Rivetti, A.; Rode, J.; Romani, A.; Romero, L.; Rossi, N.; Rubbia,
A.; Sala, P.; Salatino, P.; Samoylov, O.; Sánchez García, E.;
Sandford, E.; Sanfilippo, S.; Sant, M.; Santone, D.; Santorelli, R.;
Savarese, C.; Scapparone, E.; Schlitzer, B.; Scioli, G.; Segreto, E.;
Seifert, A.; Semenov, D. A.; Shchagin, A.; Sheshukov, A.; Siddhanta,
S.; Simeone, M.; Singh, P. N.; Skensved, P.; Skorokhvatov, M. D.;
Smirnov, O.; Sobrero, G.; Sokolov, A.; Sotnikov, A.; Stainforth, R.;
Steri, A.; Stracka, S.; Strickland, V.; Suffritti, G. B.; Sulis, S.;
Suvorov, Y.; Szelc, A. M.; Tartaglia, R.; Testera, G.; Thorpe, T.;
Tonazzo, A.; Tosi, A.; Tuveri, M.; Unzhakov, E. V.; Usai, G.; Vacca,
A.; Vázquez-Jáuregui, E.; Viant, T.; Viel, S.; Villa, F.; Vishneva,
A.; Vogelaar, R. B.; Wahl, J.; Walding, J. J.; Wang, H.; Wang, Y.;
Westerdale, S.; Wheadon, R. J.; Williams, R.; Wilson, J.; Wojcik,
Ma. M.; Wojcik, Ma.; Wu, S.; Xiao, X.; Yang, C.; Ye, Z.; Zuffa, M.;
Zuzel, G.
2020arXiv200402024T Altcode:
Proportional electroluminescence (EL) in noble gases is used in
two-phase detectors for dark matter searches to record (in the gas
phase) the ionization signal induced by particle scattering in the
liquid phase. The "standard" EL mechanism is considered to be due to
noble gas excimer emission in the vacuum ultraviolet (VUV). In addition,
there are two alternative mechanisms, producing light in the visible
and near infrared (NIR) ranges. The first is due to bremsstrahlung
of electrons scattered on neutral atoms ("neutral bremsstrahlung",
NBrS). The second, responsible for electron avalanche scintillation in
the NIR at higher electric fields, is due to transitions between excited
atomic states. In this work, we have for the first time demonstrated
two alternative techniques of the optical readout of two-phase argon
detectors, in the visible and NIR range, using a silicon photomultiplier
matrix and electroluminescence due to either neutral bremsstrahlung or
avalanche scintillation. The amplitude yield and position resolution
were measured for these readout techniques, which allowed to assess
the detection threshold for electron and nuclear recoils in two-phase
argon detectors for dark matter searches. To the best of our knowledge,
this is the first practical application of the NBrS effect in detection
science.
---------------------------------------------------------
Title: Solar Irradiance: Instrument-Based Advances
Authors: Kopp, Greg
2020IAUGA..30..354K Altcode:
Variations of the total solar irradiance (TSI) over long periods
of time provide natural Earth-climate forcing and are thus
important to monitor. Variations over a solar cycle are at the
0.1 % level. Variations on multi-decadal to century timescales are
(fortunately for our climate stability) very small, which drives the
need for highly-accurate and stable measurements over correspondingly
long periods of time to discern any such irradiance changes. Advances
to TSI-measuring space-borne instruments are approaching the desired
climate-driven measurement accuracies and on-orbit stabilities. I
present a summary of the modern-instrument improvements enabling these
measurements and present some of the solar-variability measurement
results from recent space-borne instruments, including TSI variations on
timescales from solar flares and large-scale convection to solar cycles.
---------------------------------------------------------
Title: First TSI results and status report of the CLARA/NorSat-1
solar absolute radiometer
Authors: Walter, Benjamin; Andersen, Bo; Beattie, Alexander; Finsterle,
Wolfgang; Kopp, Greg; Pfiffner, Daniel; Schmutz, Werner
2020IAUGA..30..358W Altcode:
The Compact Lightweight Absolute Radiometer (CLARA) is orbiting Earth
on-board the Norwegian NorSat-1 micro-satellite since 14<SUP>th</SUP>
of July 2017. The first light total solar irradiance (TSI) measurement
result of CLARA is 1360.18 W m<SUP>-2</SUP> for the so far single
reliable Channel B. Channel A and C measured significantly lower
(higher) TSI values and were found being sensitive to satellite pointing
instabilities. These channels most likely suffer from electrical
interference between satellite components and CLARA, an effect that
is currently under investigation. Problems with the satellite attitude
control currently inhibit stable pointing of CLARA to the Sun.
---------------------------------------------------------
Title: Solar irradiance: from multiple observations to a single
composite
Authors: Dudok de Wit, Thierry; Kopp, Greg
2020IAUGA..30..336D Altcode:
We review recent developments in combining solar irradiance datasets
from different instruments to obtain one single composite, which is
the key to understanding how irradiance varies on decadal timescales
and beyond.
---------------------------------------------------------
Title: FM9 - Solar Irradiance: Physics-Based Advances
Authors: Kopp, Greg; Shapiro, Alexander
2020IAUGA..30..331K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Design and construction of a new detector to measure ultra-low
radioactive-isotope contamination of argon
Authors: Aalseth, C. E.; Abdelhakim, S.; Acerbi, F.; Agnes, P.; Ajaj,
R.; Albuquerque, I. F. M.; Alexander, T.; Alici, A.; Alton, A. K.;
Amaudruz, P.; Ameli, F.; Anstey, J.; Antonioli, P.; Arba, M.; Arcelli,
S.; Ardito, R.; Arnquist, I. J.; Arpaia, P.; Asner, D. M.; Asunskis,
A.; Ave, M.; Back, H. O.; Barbaryan, V.; Barrado Olmedo, A.; Batignani,
G.; Bisogni, M. G.; Bocci, V.; Bondar, A.; Bonfini, G.; Bonivento, W.;
Borisova, E.; Bottino, B.; Boulay, M. G.; Bunker, R.; Bussino, S.;
Buzulutskov, A.; Cadeddu, M.; Cadoni, M.; Caminata, A.; Canci, N.;
Candela, A.; Cantini, C.; Caravati, M.; Cariello, M.; Carnesecchi,
F.; Carpinelli, M.; Castellani, A.; Castello, P.; Catalanotti, S.;
Cataudella, V.; Cavalcante, P.; Cavazza, D.; Cavuoti, S.; Cebrian,
S.; Cela Ruiz, J. M.; Celano, B.; Cereseto, R.; Cheng, W.; Chepurnov,
A.; Cicalò, C.; Cifarelli, L.; Citterio, M.; Coccetti, F.; Cocco,
A. G.; Cocco, V.; Colocci, M.; Consiglio, L.; Cossio, F.; Covone, G.;
Crivelli, P.; D'Antone, I.; D'Incecco, M.; D'Urso, D.; Da Rocha Rolo,
M. D.; Dadoun, O.; Daniel, M.; Davini, S.; De Candia, A.; De Cecco,
S.; De Deo, M.; De Falco, A.; De Filippis, G.; De Gruttola, D.; De
Guido, G.; De Rosa, G.; Dellacasa, G.; Demontis, P.; DePaquale, S.;
Derbin, A. V.; Devoto, A.; Di Eusanio, F.; Di Noto, L.; Di Pietro,
G.; Di Stefano, P.; Dionisi, C.; Dolganov, G.; Dordei, F.; Downing,
M.; Edalatfar, F.; Empl, A.; Fernandez Diaz, M.; Ferri, A.; Filip,
C.; Fiorillo, G.; Fomenko, K.; Franceschi, A.; Franco, D.; Froudakis,
G. E.; Gabriele, F.; Gabrieli, A.; Galbiati, C.; Garbini, M.; Garcia
Abia, P.; Gascón Fora, D.; Gendotti, A.; Ghiano, C.; Ghisi, A.;
Giagu, S.; Giampa, P.; Giampaolo, R. A.; Giganti, C.; Giorgi, M. A.;
Giovanetti, G. K.; Gligan, M. L.; Gola, A.; Gorchakov, O.; Grab, M.;
Graciani Diaz, R.; Granato, F.; Grassi, M.; Grate, J. W.; Grigoriev,
G. Y.; Grobov, A.; Gromov, M.; Guan, M.; Guerra, M. B. B.; Guerzoni,
M.; Gulino, M.; Haaland, R. K.; Hackett, B. R.; Hallin, A.; Harrop,
B.; Hoppe, E. W.; Horikawa, S.; Hosseini, B.; Hubaut, F.; Humble, P.;
Hungerford, E. V.; Ianni, An.; Ilyasov, A.; Ippolito, V.; Jillings,
C.; Keeter, K.; Kendziora, C. L.; Kim, S.; Kochanek, I.; Kondo, K.;
Kopp, G.; Korablev, D.; Korga, G.; Kubankin, A.; Kugathasan, R.; Kuss,
M.; Kuźniak, M.; La Commara, M.; La Delfa, L.; Lai, M.; Langrock, S.;
Lebois, M.; Lehnert, B.; Levashko, N.; Li, X.; Liqiang, Q.; Lissia,
M.; Lodi, G. U.; Longo, G.; López Manzano, R.; Lussana, R.; Luzzi,
L.; Machado, A. A.; Machulin, I. N.; Mandarano, A.; Mapelli, L.;
Marcante, M.; Margotti, A.; Mari, S. M.; Mariani, M.; Maricic, J.;
Marinelli, M.; Marras, D.; Martínez, M.; Martínez Morales, J. J.;
Martinez Rojas, A. D.; Martoff, C. J.; Mascia, M.; Mason, J.; Masoni,
A.; Mazzi, A.; McDonald, A. B.; Messina, A.; Meyers, P. D.; Miletic,
T.; Milincic, R.; Moggi, A.; Moioli, S.; Monroe, J.; Morrocchi, M.;
Mroz, T.; Mu, W.; Muratova, V. N.; Murphy, S.; Muscas, C.; Musico, P.;
Nania, R.; Napolitano, T.; Navrer Agasson, A.; Nessi, M.; Nikulin,
I.; Oleinik, A.; Oleynikov, V.; Orsini, M.; Ortica, F.; Pagani, L.;
Pallavicini, M.; Palmas, S.; Pandola, L.; Pantic, E.; Paoloni, E.;
Paternoster, G.; Pazzona, F.; Peeters, S.; Pegoraro, P. A.; Pelczar,
K.; Pellegrini, L. A.; Pellegrino, C.; Pelliccia, N.; Perotti, F.;
Pesudo, V.; Picciau, E.; Piemonte, C.; Pietropaolo, F.; Pocar,
A.; Pollmann, T. R.; Portaluppi, D.; Poudel, S. S.; Pralavorio,
P.; Price, D.; Radics, B.; Raffaelli, F.; Ragusa, F.; Razeti, M.;
Razeto, A.; Regazzoni, V.; Regenfus, C.; Renshaw, A. L.; Rescia, S.;
Rescigno, M.; Retiere, F.; Rignanese, L. P.; Rivetti, A.; Romani, A.;
Romero, L.; Rossi, N.; Rubbia, A.; Sablone, D.; Sala, P.; Salatino,
P.; Samoylov, O.; Sánchez García, E.; Sanfilippo, S.; Sant, M.;
Santone, D.; Santorelli, R.; Savarese, C.; Scapparone, E.; Schlitzer,
B.; Scioli, G.; Segreto, E.; Seifert, A.; Semenov, D. A.; Shchagin, A.;
Sheshukov, A.; Siddhanta, S.; Simeone, M.; Singh, P. N.; Skensved, P.;
Skorokhvatov, M. D.; Smirnov, O.; Sobrero, G.; Sokolov, A.; Sotnikov,
A.; Stainforth, R.; Steri, A.; Stracka, S.; Strickland, V.; Suffritti,
G. B.; Sulis, S.; Suvorov, Y.; Szelc, A. M.; Tartaglia, R.; Testera,
G.; Thorpe, T.; Tonazzo, A.; Tosi, A.; Tuveri, M.; Unzhakov, E. V.;
Usai, G.; Vacca, A.; Vázquez-Jáuregui, E.; Verducci, M.; Viant, T.;
Viel, S.; Villa, F.; Vishneva, A.; Vogelaar, R. B.; Wada, M.; Wahl,
J.; Walding, J. J.; Wang, H.; Wang, Y.; Westerdale, S.; Wheadon,
R. J.; Williams, R.; Wilson, J.; Wojcik, Marcin; Wojcik, Mariusz;
Wu, S.; Xiao, X.; Yang, C.; Ye, Z.; Zuffa, M.; Zuzel, G.
2020JInst..15P2024A Altcode: 2020arXiv200108106T
Large liquid argon detectors offer one of the best avenues for the
detection of galactic weakly interacting massive particles (WIMPs)
via their scattering on atomic nuclei. The liquid argon target allows
exquisite discrimination between nuclear and electron recoil signals via
pulse-shape discrimination of the scintillation signals. Atmospheric
argon (AAr), however, has a naturally occurring radioactive isotope,
<SUP>39</SUP>Ar, a β emitter of cosmogenic origin. For large detectors,
the atmospheric <SUP>39</SUP>Ar activity poses pile-up concerns. The use
of argon extracted from underground wells, deprived of <SUP>39</SUP>Ar,
is key to the physics potential of these experiments. The DarkSide-20k
dark matter search experiment will operate a dual-phase time projection
chamber with 50 tonnes of radio-pure underground argon (UAr), that
was shown to be depleted of <SUP>39</SUP>Ar with respect to AAr by
a factor larger than 1400. Assessing the <SUP>39</SUP>Ar content of
the UAr during extraction is crucial for the success of DarkSide-20k,
as well as for future experiments of the Global Argon Dark Matter
Collaboration (GADMC). This will be carried out by the DArT in ArDM
experiment, a small chamber made with extremely radio-pure materials
that will be placed at the centre of the ArDM detector, in the Canfranc
Underground Laboratory (LSC) in Spain. The ArDM LAr volume acts as an
active veto for background radioactivity, mostly γ-rays from the ArDM
detector materials and the surrounding rock. This article describes the
DArT in ArDM project, including the chamber design and construction,
and reviews the background required to achieve the expected performance
of the detector.
---------------------------------------------------------
Title: Overview of the NASA Solar Irradiance Science Team (SIST)
Program Special Section
Authors: DeLand, Matthew T.; Kopp, Greg; Considine, David B.
2019E&SS....6.2229D Altcode:
Solar irradiance represents the dominant energy source heating the
Earth's atmosphere and climate. Both total solar irradiance and spectral
solar irradiance vary over the 11-year solar cycle. Characterizing
these variations with sufficient accuracy for climate studies over
multidecadal timescales requires a combination of multiple observational
data sets, solar activity proxies, and irradiance models. NASA
established the Solar Irradiance Science Team (SIST) program in 2015
to pursue this goal using a range of technical approaches. This paper
summarizes those investigations, whose results are reported in separate
papers in a special section of this journal.
---------------------------------------------------------
Title: Solar Irradiance Variability: Comparisons of Models and
Measurements
Authors: Coddington, O.; Lean, J.; Pilewskie, P.; Snow, M.; Richard,
E.; Kopp, G.; Lindholm, C.; DeLand, M.; Marchenko, S.; Haberreiter,
M.; Baranyi, T.
2019E&SS....6.2525C Altcode:
The Earth system responds to solar variability on a wide range of
timescales. Knowledge of total solar irradiance (TSI) and solar
spectral irradiance (SSI) spanning minutes to centuries is needed by
scientists studying a broad array of research applications. For these
purposes, the NOAA National Centers for Environmental Information
(NCEI) Climate Data Record Program established the Solar Irradiance
Climate Data Record. Version 2 of the Naval Research Laboratory's
solar variability models that are derived from and demonstrate
consistency with irradiance observations specifies TSI and SSI for
the Solar Irradiance Climate Data Record. We establish the veracity
of the Naval Research Laboratory models on the timescales and over
the wavelength range for which the Sun is known to vary and, thereby,
specify the utility of these models. Through comparisons with irradiance
observations and independent models, we validate NRLTSI2 estimates
of TSI on solar rotational (~27-day), solar cycle (~11-year), and
multidecadal (spacecraft era) variability timescales. Similarly,
we validate NRLSSI2 estimates of SSI rotational variability in the
ultraviolet through the mid-visible spectrum. Validation of NRLSSI2
estimates at longer wavelengths, particularly in the near-infrared,
and for the full spectrum at solar cycle timescales and longer is not
possible with the current observational record due to instrumental noise
and instrument instability. We identify where key new data sets, such
as observations from the Total and Spectral Solar Irradiance Sensor-1,
are expected to provide a fuller understanding of total and spectral
solar irradiance variability on multiple timescales.
---------------------------------------------------------
Title: Compact total irradiance monitor flight demonstration
Authors: Harber, David; Castleman, Zach; Drake, Ginger; Van Dreser,
Samuel; Farber, Nat; Heuerman, Karl; Miller, Marc; Rutkowski, Joel;
Sims, Alan; Sprunck, Jacob; Straatsma, Cameron; Wanamaker, Isaac;
Zheng, Wengang; Kopp, Greg; Richard, Erik; Pilewskie, Peter; Tomlin,
Nathan; Stephens, Michelle; Yung, Christopher; White, Malcolm;
Lehman, John
2019SPIE11131E..0DH Altcode:
The long-term balance between Earth's absorption of solar
energy and emission of radiation to space is a fundamental climate
measurement. Total solar irradiance (TSI) has been measured from space,
uninterrupted, for the past 40 years via a series of instruments. The
Compact Total Irradiance Monitor (CTIM) is a CubeSat instrument that
will demonstrate next-generation technology for monitoring total solar
irradiance. It includes novel silicon-substrate room temperature
vertically aligned carbon nanotube (VACNT) bolometers. The CTIM,
an eight-channel 6U CubeSat instrument, is being built for a target
launch date in late 2020. The basic design is similar to the SORCE,
TCTE and TSIS Total Irradiance Monitors (TIM). Like TSIS TIM, it will
measure the total irradiance of the Sun with an uncertainty of 0.0097%
and a stability of <0.001%/year. The underlying technology, including
the silicon substrate VACNT bolometers, has been demonstrated at the
prototype-level. During 2019 we will build and test an engineering model
of the detector subsystem. Following the testing of the engineering
detector subsystem, we will build a flight detector unit and integrate
it with a 6U CubeSat bus during late 2019 and 2020, in preparation
for an on-orbit demonstration in 2021.
---------------------------------------------------------
Title: GPS, decrypting brightness variations of the Sun and Sun-like
Authors: Amazo-Gómez, Eliana Maritza; Shapiro, Alexander I.; Solanki,
Sami K.; Kopp, Greg; Oshagh, Mahmoudreza; Reinhold, Timo; Krivova,
Natalie A.; Reiners, Ansgar
2019shin.confE.109A Altcode:
The rotation period is in general detectable in the light curves of
young and active stars. Even after successful stellar surveys stemmed
from Kepler mission, there is still a lack of information in photometric
records of rotation periods in Sun-like stars. Non-periodic light-curve
profiles, low variability contrast -therefore low modulation amplitude-
short lifetime evolution and random emergence of magnetic features
(in comparison to the rotation time-scale) are the main reasons of
unreliable determination of rotation periodicity in the Sun and its
closer analogs. This indicates that only a small fraction of solar-like
systems have been properly analyzed. We show that the rotation periods
of those stars can be reliably determined from the profile of the
gradient of the power spectra, GPS. By analysing periodic patterns
in high-accuracy measurements of the total solar irradiance, TSI,
by SORCE/TIM and SoHO/VIRGO missions, here we test and validate
GPS, linking the variability by transits of magnetic features over
the stellar surface with a clear and enhanced signal of the solar
rotation. GPS method retrieves accurate and stable values of rotation
period during different regimes of solar activity cycle and could
be applied to stars of comparable and higher activity - where other
methods underperform. Furthermore, GPS gives us constraints on the
faculae to spot driver ratio and consequently help us to interpret
the stellar surface.
---------------------------------------------------------
Title: Response of Solar Irradiance to Sunspot-area Variations
Authors: Dudok de Wit, T.; Kopp, G.; Shapiro, A.; Witzke, V.;
Kretzschmar, M.
2018ApJ...853..197D Altcode: 2018arXiv180504350D
One of the important open questions in solar irradiance studies
is whether long-term variability (i.e., on timescales of years and
beyond) can be reconstructed by means of models that describe short-term
variability (i.e., days) using solar proxies as inputs. Preminger &
Walton showed that the relationship between spectral solar irradiance
and proxies of magnetic-flux emergence, such as the daily sunspot area,
can be described in the framework of linear system theory by means of
the impulse response. We significantly refine that empirical model
by removing spurious solar-rotational effects and by including an
additional term that captures long-term variations. Our results show
that long-term variability cannot be reconstructed from the short-term
response of the spectral irradiance, which questions the extension of
solar proxy models to these timescales. In addition, we find that the
solar response is nonlinear in a way that cannot be corrected simply
by applying a rescaling to a sunspot area.
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Title: A New Revision of the Solar Irradiance Climate Data Record
Incorporates Recent Research into Proxies of Sunspot Darkening and
the Sunspot Number Record
Authors: Coddington, O.; Lean, J.; Pilewskie, P.; Baranyi, T.; Snow,
M. A.; Kopp, G.; Richard, E. C.; Lindholm, C.
2017AGUFMSH43B2818C Altcode:
An operational climate data record (CDR) of total and spectral solar
irradiance became available in November 2015 as part of the National
Oceanographic and Atmospheric Administration's National Centers for
Environmental Information Climate Data Record Program. The data record,
which is updated quarterly, is available from 1610 to the present
as yearly-average values and from 1882 to the present as monthly-
and daily-averages, with associated time and wavelength-dependent
uncertainties. It was developed jointly by the University of Colorado
at Boulder's Laboratory for Atmospheric and Space Physics and the Naval
Research Laboratory, and, together with the source code and supporting
documentation, is available at https://www.ncdc.noaa.gov/cdr/. In the
Solar Irradiance CDR, total solar irradiance (TSI) and solar spectral
irradiance (SSI) are estimated from models that determine the changes
from quiet Sun conditions arising from bright faculae and dark sunspots
on the solar disk. The models are constructed using linear regression of
proxies of solar sunspot and facular features with the approximately
decade-long irradiance observations from the SOlar Radiation and
Climate Experiment. A new revision of this data record was recently
released in an ongoing effort to reduce solar irradiance uncertainties
in two ways. First, the sunspot darkening proxy was revised using
a new cross calibration of the current sunspot region observations
made by the Solar Observing Optical Network with the historical
records of the Royal Greenwich Observatory. This implementation
affects modeled irradiances from 1882 - 1978. Second, the impact of a
revised record of sunspot number by the Sunspot Index and Long-term
Solar Observations center on modeled irradiances was assessed. This
implementation provides two different reconstructions of historical,
yearly-averaged irradiances from 1610-1881. Additionally, we show new,
preliminary results that demonstrate improvements in modeled TSI by
using Debrecen Photoheliographic sunspot area and location data produced
by the Debrecen Heliophysical Observatory as the proxy of sunspot
darkening. Our results describe comparisons of the modeled TSI and
SSI with observational records and with other solar irradiance models.
---------------------------------------------------------
Title: Methodology to create a new total solar irradiance record:
Making a composite out of multiple data records
Authors: Dudok de Wit, Thierry; Kopp, Greg; Fröhlich, Claus;
Schöll, Micha
2017GeoRL..44.1196D Altcode: 2017arXiv170202341D
Many observational records critically rely on our ability to merge
different (and not necessarily overlapping) observations into a single
composite. We provide a novel and fully traceable approach for doing
so, which relies on a multiscale maximum likelihood estimator. This
approach overcomes the problem of data gaps in a natural way and uses
data-driven estimates of the uncertainties. We apply it to the total
solar irradiance (TSI) composite, which is currently being revised and
is critical to our understanding of solar radiative forcing. While the
final composite is pending decisions on what corrections to apply to
the original observations, we find that the new composite is in closest
agreement with the PMOD composite and the NRLTSI2 model. In addition, we
evaluate long-term uncertainties in the TSI, which reveal a 1/f scaling.
---------------------------------------------------------
Title: How to Establish Traceability for Total Solar Irradiance Data
to Ground-Based Standards
Authors: Finsterle, W.; Walter, B.; Kopp, G.
2016AGUFMSH31B2557F Altcode:
Total Solar Irradiance (TSI) has been measured with radiometers from
space continuously since 1978. The observed TSI variations are mostly
attributed to the solar activity cycle and longer-term trends are
not unambiguously detected in the available TSI record. Nevertheless
have such trends likely occurred in the past and are also expected to
occur in the future. Because of the dominant role that TSI plays in the
Earth's energy budget even small trends are likely to have signficant
effects on the climate and the global temperature. In order to detect
such trends, the TSI the data from separate radiometers have to be
made comparable, ideally through traceability of their measurements to
ground-based irradiance standards. We will present how the traceability
chain is established for the upcoming CLARA/NORSAT-1 mission and review
the traceability of previous TSI measurements.
---------------------------------------------------------
Title: The New Climate Data Record of Solar Irradiance: Comparisons
with Observations and Solar Irradiance Models Over a Range of Solar
Activity Time Scales
Authors: Coddington, O.; Lean, J.; Pilewskie, P.; Richard, E. C.;
Snow, M. A.; Kopp, G.; Lindholm, C.
2016AGUFMSA54A..02C Altcode:
A new publically available climate data record (CDR) of total and
spectral solar irradiance became operational in November 2015 as
part of the National Oceanographic and Atmospheric Administration's
(NOAA's) National Centers for Environmental Information (NCEI) Climate
Data Record Program. The data record, which is updated regularly,
is available from 1610 to the present day as yearly-average values
and from 1882 to the present day as monthly- and daily-averages, with
associated time and wavelength-dependent uncertainties. It was developed
jointly by the University of Colorado at Boulder's Laboratory for
Atmospheric and Space Physics (LASP) and the Naval Research Laboratory
(NRL) and, together with the source code and supporting documentation,
is available at https://www.ncdc.noaa.gov/cdr/. Total solar irradiance
(TSI) and solar spectral irradiance (SSI) are estimated from models
that determine the changes from quiet Sun conditions arising from bright
faculae and dark sunspots on the solar disk. The models are constructed
using linear regression of proxies of solar sunspot and facular features
with the approximately decade-long irradiance observations from the
SOlar Radiation and Climate Experiment (SORCE). We describe the model
formulation, uncertainty estimates, and validation approach. We present
comparisons of the modeled TSI and SSI with observational records and
with other solar irradiance models on solar-rotational, solar-cycle,
and multi-decadal timescales. We discuss ongoing efforts to improve the
irradiance uncertainty estimates arising from model assumptions and
the operational approach to make these updated uncertainty estimates
publicly available in a future revision of the Solar Irradiance CDR.
---------------------------------------------------------
Title: The Impact of the Revised Sunspot Record on Solar Irradiance
Reconstructions
Authors: Kopp, G.; Krivova, N.; Wu, C. J.; Lean, J.
2016SoPh..291.2951K Altcode: 2016SoPh..tmp...42K; 2016arXiv160105397K
Reliable historical records of the total solar irradiance (TSI)
are needed to assess the extent to which long-term variations in the
Sun's radiant energy that is incident upon Earth may exacerbate (or
mitigate) the more dominant warming in recent centuries that is due
to increasing concentrations of greenhouse gases. We investigate the
effects that the new Sunspot Index and Long-term Solar Observations
(SILSO) sunspot-number time series may have on model reconstructions
of the TSI. In contemporary TSI records, variations on timescales
longer than about a day are dominated by the opposing effects
of sunspot darkening and facular brightening. These two surface
magnetic features, retrieved either from direct observations or from
solar-activity proxies, are combined in TSI models to reproduce the
current TSI observational record. Indices that manifest solar-surface
magnetic activity, in particular the sunspot-number record, then enable
reconstructing historical TSI. Revisions of the sunspot-number record
therefore affect the magnitude and temporal structure of TSI variability
on centennial timescales according to the model reconstruction methods
that are employed. We estimate the effects of the new SILSO record on
two widely used TSI reconstructions, namely the NRLTSI2 and the SATIRE
models. We find that the SILSO record has little effect on either model
after 1885, but leads to solar-cycle fluctuations with greater amplitude
in the TSI reconstructions prior. This suggests that many eighteenth-
and nineteenth-century cycles could be similar in amplitude to those
of the current Modern Maximum. TSI records based on the revised sunspot
data do not suggest a significant change in Maunder Minimum TSI values,
and from comparing this era to the present, we find only very small
potential differences in the estimated solar contributions to the
climate with this new sunspot record.
---------------------------------------------------------
Title: The 2016 Transit of Mercury Observed from Major Solar
Telescopes and Satellites
Authors: Pasachoff, Jay M.; Schneider, Glenn; Gary, Dale; Chen, Bin;
Sterling, Alphonse C.; Reardon, Kevin P.; Dantowitz, Ronald; Kopp,
Greg A.
2016DPS....4811705P Altcode:
We report observations from the ground and space of the 9 May 2016
transit of Mercury. We build on our explanation of the black-drop
effect in transits of Venus based on spacecraft observations of the 1999
transit of Mercury (Schneider, Pasachoff, and Golub, Icarus 168, 249,
2004). In 2016, we used the 1.6-m New Solar Telescope at the Big Bear
Solar Observatory with active optics to observe Mercury's transit at
high spatial resolution. We again saw a small black-drop effect as 3rd
contact neared, confirming the data that led to our earlier explanation
as a confluence of the point-spread function and the extreme solar
limb darkening (Pasachoff, Schneider, and Golub, in IAU Colloq. 196,
2004). We again used IBIS on the Dunn Solar Telescope of the Sacramento
Peak Observatory, as A. Potter continued his observations, previously
made at the 2006 transit of Mercury, at both telescopes of the sodium
exosphere of Mercury (Potter, Killen, Reardon, and Bida, Icarus 226,
172, 2013). We imaged the transit with IBIS as well as with two RED
Epic IMAX-quality cameras alongside it, one with a narrow passband. We
show animations of our high-resolution ground-based observations along
with observations from XRT on JAXA's Hinode and from NASA's Solar
Dynamics Observatory. Further, we report on the limit of the transit
change in the Total Solar Irradiance, continuing our interest from
the transit of Venus TSI (Schneider, Pasachoff, and Willson, ApJ 641,
565, 2006; Pasachoff, Schneider, and Willson, AAS 2005), using NASA's
SORCE/TIM and the Air Force's TCTE/TIM. See http://transitofvenus.info
and http://nicmosis.as.arizona.edu.Acknowledgments: We were glad for
the collaboration at Big Bear of Claude Plymate and his colleagues of
the staff of the Big Bear Solar Observatory. We also appreciate the
collaboration on the transit studies of Robert Lucas (Sydney, Australia)
and Evan Zucker (San Diego, California). JMP appreciates the sabbatical
hospitality of the Division of Geosciences and Planetary Sciences of
the California Institute of Technology, and of Prof. Andrew Ingersoll
there. The solar observations lead into the 2017 eclipse studies,
for which JMP is supported by grants from the NSF AGS and National
Geographic CRE.
---------------------------------------------------------
Title: Nominal Values for Selected Solar and Planetary Quantities:
IAU 2015 Resolution B3
Authors: Prša, Andrej; Harmanec, Petr; Torres, Guillermo; Mamajek,
Eric; Asplund, Martin; Capitaine, Nicole; Christensen-Dalsgaard,
Jørgen; Depagne, Éric; Haberreiter, Margit; Hekker, Saskia; Hilton,
James; Kopp, Greg; Kostov, Veselin; Kurtz, Donald W.; Laskar, Jacques;
Mason, Brian D.; Milone, Eugene F.; Montgomery, Michele; Richards,
Mercedes; Schmutz, Werner; Schou, Jesper; Stewart, Susan G.
2016AJ....152...41P Altcode: 2016arXiv160509788P
In this brief communication we provide the rationale for and the
outcome of the International Astronomical Union (IAU) resolution
vote at the XXIXth General Assembly in Honolulu, Hawaii, in 2015,
on recommended nominal conversion constants for selected solar and
planetary properties. The problem addressed by the resolution is a lack
of established conversion constants between solar and planetary values
and SI units: a missing standard has caused a proliferation of solar
values (e.g., solar radius, solar irradiance, solar luminosity, solar
effective temperature, and solar mass parameter) in the literature,
with cited solar values typically based on best estimates at the time
of paper writing. As precision of observations increases, a set of
consistent values becomes increasingly important. To address this, an
IAU Working Group on Nominal Units for Stellar and Planetary Astronomy
formed in 2011, uniting experts from the solar, stellar, planetary,
exoplanetary, and fundamental astronomy, as well as from general
standards fields to converge on optimal values for nominal conversion
constants. The effort resulted in the IAU 2015 Resolution B3, passed at
the IAU General Assembly by a large majority. The resolution recommends
the use of nominal solar and planetary values, which are by definition
exact and are expressed in SI units. These nominal values should be
understood as conversion factors only, not as the true solar/planetary
properties or current best estimates. Authors and journal editors are
urged to join in using the standard values set forth by this resolution
in future work and publications to help minimize further confusion.
---------------------------------------------------------
Title: Magnitudes and timescales of total solar irradiance variability
Authors: Kopp, Greg
2016JSWSC...6A..30K Altcode: 2016arXiv160605258K
The Sun's net radiative output varies on timescales of minutes to
gigayears. Direct measurements of the total solar irradiance (TSI)
show changes in the spatially- and spectrally-integrated radiant
energy on timescales as short as minutes to as long as a solar
cycle. Variations of ~0.01% over a few minutes are caused by the
ever-present superposition of convection and oscillations with very
large solar flares on rare occasion causing slightly-larger measurable
signals. On timescales of days to weeks, changing photospheric magnetic
activity affects solar brightness at the ~0.1% level. The 11-year
solar cycle shows variations of comparable magnitude with irradiances
peaking near solar maximum. Secular variations are more difficult
to discern, being limited by instrument stability and the relatively
short duration of the space-borne record. Historical reconstructions
of the Sun's irradiance based on indicators of solar-surface magnetic
activity, such as sunspots, faculae, and cosmogenic isotope records,
suggest solar brightness changes over decades to millennia, although
the magnitudes of these variations have high uncertainties due to
the indirect historical records on which they rely. Stellar evolution
affects yet longer timescales and is responsible for the greatest solar
variabilities. In this manuscript I summarize the Sun's variability
magnitudes over different temporal regimes and discuss the irradiance
record's relevance for solar and climate studies as well as for
detections of exo-solar planets transiting Sun-like stars.
---------------------------------------------------------
Title: The Next Spaceflight Solar Irradiance Sensor: TSIS
Authors: Kopp, Greg; Pilewskie, Peter; Richard, Erik
2016SPD....47.0809K Altcode:
The Total and Spectral Solar Irradiance Sensor (TSIS) will continue
measurements of the solar irradiance with improved accuracies
and stabilities over extant spaceflight instruments. The two TSIS
solar-observing instruments include the Total Irradiance Monitor
(TIM) and the Spectral Irradiance Monitor (SIM) for measuring total-
and spectral- solar-irradiance, respectively. The former provides the
net energy powering the Earth’s climate system while the latter helps
attribute where that energy is absorbed by the Earth’s atmosphere and
surface. Both spaceflight instruments are assembled and being prepared
for integration on the International Space Station. With operations
commencing in late 2017, the TSIS is intended to overlap with NASA’s
ongoing SOlar Radiation and Climate Experiment (SORCE) mission,
which launched in 2003 and contains the first versions of both the
TIM and SIM instruments, as well as with the TSI Calibration Transfer
Experiment (TCTE), which began total solar irradiance measurements in
2013. We summarize the TSIS’s instrument improvements and intended
solar-irradiance measurements.
---------------------------------------------------------
Title: The Impact of the Revised Sunspot Record on Solar Irradiance
Reconstructions
Authors: Kopp, G.; Krivova, N.; Lean, J.; Wu, C. J.
2015AGUFMSH23C2451K Altcode:
We describe the expected effects of the new sunspot number time series
on proxy model based reconstructions of the total solar irradiance
(TSI), which is largely explained by the opposing effects of dark
sunspots and bright faculae. Regressions of indices for facular
brightening and sunspot darkening with time series of direct TSI
observations during the recent 37-year spacecraft TSI measurement
era determine the relative contributions from each. Historical TSI
reconstructions are enabled by extending these proxy models back in time
prior to the start of the measurement record using a variety of solar
activity indices including the sunspot number time series alone prior
to 1882. Such reconstructions are critical for Earth climate research,
which requires knowledge of the incident energy from the Sun to assess
climate sensitivity to the natural influence of solar variability. Two
prominent TSI reconstructions that utilize the sunspot record starting
in 1610 are the NRLTSI and the SATIRE models. We review the indices
that each currently uses and estimate the effects the revised sunspot
record has on these reconstructions.
---------------------------------------------------------
Title: Solar Variability Magnitudes and Timescales
Authors: Kopp, Greg
2015IAUGA..2251303K Altcode:
The Sun’s net radiative output varies on timescales of minutes to many
millennia. The former are directly observed as part of the on-going
37-year long total solar irradiance climate data record, while the
latter are inferred from solar proxy and stellar evolution models. Since
the Sun provides nearly all the energy driving the Earth’s climate
system, changes in the sunlight reaching our planet can have - and
have had - significant impacts on life and civilizations.Total solar
irradiance has been measured from space since 1978 by a series of
overlapping instruments. These have shown changes in the spatially-
and spectrally-integrated radiant energy at the top of the Earth’s
atmosphere from timescales as short as minutes to as long as a solar
cycle. The Sun’s ~0.01% variations over a few minutes are caused by
the superposition of convection and oscillations, and even occasionally
by a large flare. Over days to weeks, changing surface activity affects
solar brightness at the ~0.1% level. The 11-year solar cycle has
comparable irradiance variations with peaks near solar maxima.Secular
variations are harder to discern, being limited by instrument stability
and the relatively short duration of the space-borne record. Proxy
models of the Sun based on cosmogenic isotope records and inferred
from Earth climate signatures indicate solar brightness changes over
decades to millennia, although the magnitude of these variations depends
on many assumptions. Stellar evolution affects yet longer timescales
and is responsible for the greatest solar variabilities.In this talk
I will summarize the Sun’s variability magnitudes over different
temporal ranges, showing examples relevant for climate studies as well
as detections of exo-solar planets transiting Sun-like stars.
---------------------------------------------------------
Title: The Total Irradiance Monitors
Authors: Kopp, Greg
2015IAUGA..2251309K Altcode:
The first Total Irradiance Monitor (TIM) launched on NASA’s Solar
Radiation and Climate Experiment in 2003 and quickly proved to be the
most accurate and stable instrument on orbit for measuring the total
solar irradiance (TSI). The TIM’s design improvements over the older
classical radiometers helped its selection on many subsequent missions,
including NASA’s Glory, NOAA’s TSI Calibration Transfer Experiment,
and the series of NASA’s Total and Spectral Solar Irradiance
Sensor instruments currently underway. I will summarize the status
of and differences between each of the TIMs currently on-orbit or
in production.
---------------------------------------------------------
Title: The solar magnetic activity band interaction and instabilities
that shape quasi-periodic variability
Authors: McIntosh, Scott W.; Leamon, Robert J.; Krista, Larisza D.;
Title, Alan M.; Hudson, Hugh S.; Riley, Pete; Harder, Jerald W.; Kopp,
Greg; Snow, Martin; Woods, Thomas N.; Kasper, Justin C.; Stevens,
Michael L.; Ulrich, Roger K.
2015NatCo...6.6491M Altcode: 2015NatCo...6E6491M
Solar magnetism displays a host of variational timescales of which
the enigmatic 11-year sunspot cycle is most prominent. Recent work
has demonstrated that the sunspot cycle can be explained in terms of
the intra- and extra-hemispheric interaction between the overlapping
activity bands of the 22-year magnetic polarity cycle. Those
activity bands appear to be driven by the rotation of the Sun's
deep interior. Here we deduce that activity band interaction can
qualitatively explain the `Gnevyshev Gap'--a well-established feature
of flare and sunspot occurrence. Strong quasi-annual variability in the
number of flares, coronal mass ejections, the radiative and particulate
environment of the heliosphere is also observed. We infer that this
secondary variability is driven by surges of magnetism from the activity
bands. Understanding the formation, interaction and instability of
these activity bands will considerably improve forecast capability in
space weather and solar activity over a range of timescales.
---------------------------------------------------------
Title: Sorce Observations of Solar Cycles 23 and 24 - What's
New? What's Next?
Authors: Cahalan, R. F.; Kopp, G.; Pilewskie, P.; Richard, E. C.;
Woods, T. N.
2014AGUFMSH21C4131C Altcode:
We discuss recent changes in estimates of the Total Solar Irradiance
(TSI, formerly "solar constant") and the energy budget. This more
accurate value of TSI implies a more accurate estimate of the Sun's
luminosity, and lifetime. We highlight the historic closing of the
calibration gap between the suite of TSI instruments, due largely to
comparisons made with a cryogenic Transfer Radiometer Facility (TRF)
located at the University of Colorado, built by UCO/LASP with support
from NASA and NIST. The resulting continuous record of TSI promises
to be a milestone in improving understanding of the Sun's impact on
Earth's climate. Climate models are sensitive not only to TSI, but
also to variations in the Spectral Solar Irradiance (SSI), and the
vertical profiles of temperature and ozone are especially sensitive to
SSI variations. Variations in SSI need further study before they may
be considered as firmly established as TSI variations, which themselves
remain controversial, despite a strengthening consensus over the SORCE
epoch. The TSIS SIM has recently undergone comprehensive end-to-end
calibration in the LASP SSI Radiometry Facility (SRF) utilizing the
NIST SIRCUS laser system covering 210-2400 nm for SSI, a facility
not yet available when SORCE launched in 2003. With SORCE follow-on
missions such as the Total and Spectral Solar Irradiance Sensor (TSIS),
we anticipate narrowing uncertainties in SSI variability that will be
important to improving our understanding of the climate responses to
solar forcing. The long-term goal of improving the ability to monitor
Earth's energy balance, and the energy imbalance that drives global
warming, will need continued improvements in the measurement of both
shortwave solar and longwave earth-emitted radiation.
---------------------------------------------------------
Title: White-Light Observations of Major Flares Compared to Total
Solar Irradiance and Short-Wavelength Observations
Authors: Petrie, Gordon; Kopp, Greg; Harvey, J. W.
2014AAS...22412327P Altcode:
The NSO’s GONG network produces “white light” (WL) continuum
intensity images from one-minute integrations averaged across a 0. Å
wide band pass centered at 676 Å at one minute cadence using six
sites worldwide. Clear WL signatures of solar flares are present in
GONG intensity data for only the largest flares because of low spatial
resolution (2.5 arcsec pixel size). For six major flares (GOES class
X6.5 - X28) observed by GONG, we compare integrated GONG full-disk
WL intensity curves with SORCE/TIM total solar irradiance (TSI)
measurements. Distinctive p-mode signatures are evident in both GONG
and SORCE time series, though the correlation between GONG and SORCE
data varies from flare to flare. In some cases a clear TSI peak and an
interruption of the GONG p-mode pattern accompany the flare. The flare
signature is generally weaker in the GONG data, suggesting that most of
the TIM flare signal arises from wavelengths shorter than the GONG band
pass. The flare kernels nevertheless are clear and last many minutes
in the spatially resolved GONG image time series. We also compare
the GONG active region intensity observations with shorter-wavelength
data. In one case observed by TRACE, the GONG and TRACE WL curves are
very similar and the TRACE 160 Å curve shows a significant precursor
and a long tail. In most cases the GONG WL and RHESSI 25-100 keV counts
appear well correlated in time. This work utilizes GONG data obtained
by the NSO Integrated Synoptic Program (NISP), managed by the National
Solar Observatory, which is operated by AURA, Inc. under a cooperative
agreement with the National Science Foundation.
---------------------------------------------------------
Title: An assessment of the solar irradiance record for climate
studies
Authors: Kopp, Greg
2014JSWSC...4A..14K Altcode:
Total solar irradiance, the spatially and spectrally integrated radiant
output from the Sun at a mean Sun-Earth distance of 1 astronomical
unit, provides nearly all the energy driving the Earth's climate
system. Variations in this energy, particularly over long time scales,
contribute to changes in Earth's climate and have been linked to
historical glaciation and inter-glacial periods as well as having a
small effect on more recent global warming. Accurate measurements of
solar irradiances require measurements above the Earth's atmosphere. The
total solar irradiance spaceborne record began in 1978 and has been
uninterrupted since, with over a dozen instruments contributing to the
present solar climate data record. I assess the required and achieved
accuracies of this record with a focus on its value for climate studies.
---------------------------------------------------------
Title: Three 2012 Transits of Venus: From Earth, Jupiter, and Saturn
Authors: Pasachoff, Jay M.; Schneider, G.; Babcock, B. A.; Lu, M.;
Edelman, E.; Reardon, K.; Widemann, T.; Tanga, P.; Dantowitz, R.;
Silverstone, M. D.; Ehrenreich, D.; Vidal-Madjar, A.; Nicholson,
P. D.; Willson, R. C.; Kopp, G. A.; Yurchyshyn, V. B.; Sterling,
A. C.; Scherrer, P. H.; Schou, J.; Golub, L.; McCauley, P.; Reeves, K.
2013AAS...22131506P Altcode:
We observed the 2012 June 6/5 transit seen from Earth (E/ToV),
simultaneously with Venus Express and several other spacecraft
not only to study the Cytherean atmosphere but also to provide an
exoplanet-transit analog. From Haleakala, the whole transit was visible
in coronal skies; among our instruments was one of the world-wide Venus
Twilight Experiment's nine coronagraphs. Venus's atmosphere became
visible before first contact. SacPeak/IBIS provided high-resolution
images at Hα/carbon-dioxide. Big Bear's NST also provided
high-resolution observations of the Cytherean atmosphere and black-drop
evolution. Our liaison with UH's Mees Solar Observatory scientists
provided magneto-optical imaging at calcium and potassium. Solar
Dynamics Observatory's AIA and HMI, and the Solar Optical Telescope
(SOT) and X-ray Telescope (XRT) on Hinode, and total-solar-irradiance
measurements with ACRIMSAT and SORCE/TIM, were used to observe the
event as an exoplanet-transit analog. On September 20, we imaged
Jupiter for 14 Hubble Space Telescope orbits, centered on a 10-hour
ToV visible from Jupiter (J/ToV), as an exoplanet-transit analog in
our own solar system, using Jupiter as an integrating sphere. Imaging
was good, although much work remains to determine if we can detect
the expected 0.01% solar irradiance decrease at Jupiter and the even
slighter differential effect between our violet and near-infrared
filters caused by Venus's atmosphere. We also give a first report on our
currently planned December 21 Cassini UVIS observations of a transit of
Venus from Saturn (S/ToV). Our E/ToV expedition was sponsored by the
Committee for Research and Exploration/National Geographic Society;
supplemented: NASA/AAS's Small Research Grant Program. We thank Rob
Ratkowski, Stan Truitt, Rob Lucas, Aram Friedman, and Eric Pilger
'82 at Haleakala, and Joseph Gangestad '06 at Big Bear for assistance,
and Lockheed Martin Solar and Astrophysics Lab and Hinode science and
operations teams for support for coordinated observations with NASA
satellites. Our J/ToV observations were based on observations made
with HST, operated by AURA, Inc., under NASA contract NAS 5-26555;
these observations are associated with program #13067.
---------------------------------------------------------
Title: The 2012 Transit of Venus for Cytherean Atmospheric Studies
and as an Exoplanet Analog
Authors: Pasachoff, Jay M.; Schneider, G.; Babcock, B. A.; Lu, M.;
Reardon, K. P.; Widemann, T.; Tanga, P.; Dantowitz, R.; Willson,
R.; Kopp, G.; Yurchyshyn, V.; Sterling, A.; Scherrer, P.; Schou, J.;
Golub, L.; Reeves, K.
2012DPS....4450806P Altcode:
We worked to assemble as complete a dataset as possible for the
Cytherean atmosphere in collaboration with Venus Express in situ
and to provide an analog of spectral and total irradiance exoplanet
measurements. From Haleakala, the whole transit was visible in
coronal skies; our B images showed the evolution of the visibility
of Venus's atmosphere and of the black-drop effect, as part of the
Venus Twilight Experiment's 9 coronagraphs distributed worldwide
with BVRI. We imaged the Cytherean atmosphere over two minutes before
first contact, with subarcsecond resolution, with the coronagraph and
a separate refractor. The IBIS imaging spectrometer at Sacramento
Peak Observatory at H-alpha and carbon-dioxide also provided us
high-resolution imaging. The NST of Big Bear Solar Observatory
also provided high-resolution vacuum observations of the Cytherean
atmosphere and black drop evolution. Our liaison with UH's Mees Solar
Observatory scientists provided magneto-optical imaging at calcium
and potassium. Spaceborne observations included the Solar Dynamics
Observatory's AIA and HMI, and the Solar Optical Telescope (SOT)
and X-ray Telescope (XRT) on Hinode, and total-solar-irradiance
measurements with ACRIMSAT and SORCE/TIM, to characterize the
event as an exoplanet-transit analog. Our expedition was sponsored
by the Committee for Research and Exploration/National Geographic
Society. Some of the funds for the carbon-dioxide filter for IBIS were
provided by NASA through AAS's Small Research Grant Program. We thank
Rob Lucas, Aram Friedman, and Eric Pilger '82 for assistance with
Haleakala observing, Rob Ratkowski of Haleakala Amateur Astronomers
for assistance with equipment and with the site, Stan Truitt for the
loan of his Paramount ME, and Steve Bisque/Software Bisque for TheSky
X controller. We thank Joseph Gangestad '06 of Aerospace Corp., a
veteran of our 2004 expedition, for assistance at Big Bear. We thank
the Lockheed Martin Solar and Astrophysics Laboratory and Hinode
science and operations teams for planning and support.
---------------------------------------------------------
Title: The Solar Cycle 23 - 24 Minimum. A Benchmark in Solar
Variability and Effects in the Heliosphere
Authors: White, O.; Kopp, G.; Snow, M.; Tapping, K.
2011SoPh..274..159W Altcode:
Given the numerous ground-based and space-based experiments producing
the database for the Cycle 23 - 24 Minimum epoch from September 2008
to May 2009, we have an extraordinary opportunity to understand its
effects throughout the heliosphere. We use solar radiative output
in this period to obtain minimum values for three measures of the
Sun's radiative output: the total solar irradiance, the Mg II index,
and the 10.7 cm solar radio flux. The derived values are included in
the research summaries as a means to exchange ideas and data for this
long minimum in solar activity.
---------------------------------------------------------
Title: PREMOS Absolute Radiometer Calibration and Implications to
on-orbit Measurements of the Total Solar Irradiance
Authors: Fehlmann, A.; Kopp, G.; Schmutz, W. K.; Winkler, R.;
Finsterle, W.; Fox, N.
2011AGUFMGC21C..05F Altcode:
On orbit measurements starting in the late 1970's, have revealed the 11
year cycle of the Total Solar Irradiance (TSI). However, the absolute
results from individual experiments differ although all instrument
teams claim to measure an absolute value. Especially the data from the
TIM/SORCE experiment confused the community as it measures 0.3 % lower
than the other instruments, e.g. VIRGO/SOHO by PMOD/WRC, which clearly
exceeds the uncertainty stated for the absolute characterization of the
experiments. The PREMOS package on the PICARD platform launched in June
2010 is the latest space experiment by PMOD/WRC measuring the TSI. We
have put great effort in the calibration and characterization of this
instrument in order to resolve the inter-instrument differences. We
performed calibrations at the National Physical Laboratory (NPL) in
London and the Laboratory for Atmospheric and Space Physics (LASP)
in Boulder against national SI standards for radiant power using a
laser beam with a diameter being smaller than the aperture of the
instrument. These measurements together with the World Radiometric
Reference (WRR) calibration in Davos allowed to compare the WRR and
the SI radiant power scale. We found that the WRR lies 0.18 % above
the SI radiant power scale which explains a part of the VIRGO-TIM
difference. The Total solar irradiance Radiometer Facility (TRF) at
the LASP allows to generate a beam that over fills the apertures of
our instruments, giving the presently best available representation
of solar irradiance in a laboratory. These irradiance calibrations
revealed a stray light contribution between 0.09 and 0.3 % to the
measurements which had been underestimated in the characterization
of our instruments. Using the irradiance calibrations, we found that
the WRR lies 0.32 % above the TRF scale which in turn explains the
full VIRGO-TIM difference. The first light PREMOS measurements in
space confirmed our findings. If we use the WRR calibration, PREMOS
yields a TSI value of 1365.5 ± 1.2 W/m<SUP>2</SUP> (k=1) which is
in excellent agreement with VIRGO (1365.4 W/m<SUP>2</SUP>). Else,
applying the TRF calibration to PREMOS, we obtain a TSI value of 1360.9
± 0.4 W/m<SUP>2</SUP> (k=1) which is in excellent agreement with TIM
(1361.3 W/m<SUP>2</SUP>).
---------------------------------------------------------
Title: Characterization of the DARA solar absolute radiometer
Authors: Finsterle, W.; Suter, M.; Fehlmann, A.; Kopp, G.
2011AGUFMGC21C..07F Altcode:
The Davos Absolute Radiometer (DARA) prototype is an Electrical
Substitution Radiometer (ESR) which has been developed as a successor
of the PMO6 type on future space missions and ground based TSI
measurements. The DARA implements an improved thermal design of
the cavity detector and heat sink assembly to minimize air-vacuum
differences and to maximize thermal symmetry of measuring and
compensating cavity. The DARA also employs an inverted viewing geometry
to reduce internal stray light. We will report on the characterization
and calibration experiments which were carried out at PMOD/WRC and LASP
(TRF).
---------------------------------------------------------
Title: An Improved Total Solar Irradiance Climate Data Record
Authors: Kopp, G.
2011AGUFMGC21C..03K Altcode:
The dominant driver of the Earth's climate system is the Sun, which
exceeds all other energy sources combined by a factor of 2500. Small as
they are, variations in the enormous amount of energy received from the
Sun can have climatic effects on the Earth over annual to millennial
time scales. Climate studies rely on recent spaceborne measurements of
total solar irradiance (TSI) and estimates of its historical variability
to discern natural from anthropogenic climatic influences. Because the
Sun is relatively stable, the TSI measurements providing this solar
record must be of high accuracy, extremely good stability, and long
duration. New instrument calibrations and diagnostics have improved the
accuracy of the existing record and future instruments promise further
improvements. I will discuss the status of the current solar climate
data record based on recent findings, explain the climate-driven solar
irradiance measurement requirements, show estimates of solar influences
on climate, and give an overview of planned missions to provide this
needed record for climate studies.
---------------------------------------------------------
Title: Infrared Cavity Radiometer Reflectometry in Support of Total
Solar Irradiance Instruments
Authors: Hanssen, L. M.; Zeng, J.; Wilthan, B.; Morrill, J. S.;
Kopp, G.
2011AGUFMGC23A0911H Altcode:
A key component required to achieve a high degree of accuracy in
satellite solar irradiance measurements using cavity radiometers,
is the characterization of the cavity spectral absorptance over
the broad spectral range of the Solar output. This includes the
infrared region up to at least 10 μm. In order to accurately measure
high levels of absorptance of cavities, NIST has developed a laser
and integrating sphere based facility (the Complete Hemispherical
Infrared Laser-based Reflectometer (CHILR)). The system is used for
both radiometer and blackbody cavity characterization. We report the
results of reflectance (1 - absorptance) measurements of radiometer
cavities designed for two solar irradiance measurement instruments:
1) the Active Cavity Radiometer Irradiance Monitor (ACRIM) and 2)
the Total Irradiance Monitor (TIM) instrument on the SORCE and TSIS
missions. The measurements were made using the NIST CHILR instrument as
well as the Infrared Reference Integrating Sphere (IRIS) for relative
spectral reflectance. The IRIS was used to obtain relative spectral
reflectance for the TIM cones. The IRIS was also used to obtain the
spectral reflectance of other surfaces in the ACRIM instrument that
also interact with the incident irradiance and potentially affect the
cavity performance. These reflectance results are used to validate
previously estimated performance parameters of the two instruments.
---------------------------------------------------------
Title: A new, lower value of total solar irradiance: Evidence and
climate significance
Authors: Kopp, Greg; Lean, Judith L.
2011GeoRL..38.1706K Altcode: 2011GeoRL..3801706K
The most accurate value of total solar irradiance during the 2008
solar minimum period is 1360.8 ± 0.5 W m<SUP>-2</SUP> according
to measurements from the Total Irradiance Monitor (TIM) on NASA's
Solar Radiation and Climate Experiment (SORCE) and a series of new
radiometric laboratory tests. This value is significantly lower than the
canonical value of 1365.4 ± 1.3 W m<SUP>-2</SUP> established in the
1990s, which energy balance calculations and climate models currently
use. Scattered light is a primary cause of the higher irradiance values
measured by the earlier generation of solar radiometers in which the
precision aperture defining the measured solar beam is located behind
a larger, view-limiting aperture. In the TIM, the opposite order
of these apertures precludes this spurious signal by limiting the
light entering the instrument. We assess the accuracy and stability
of irradiance measurements made since 1978 and the implications of
instrument uncertainties and instabilities for climate research in
comparison with the new TIM data. TIM's lower solar irradiance value
is not a change in the Sun's output, whose variations it detects
with stability comparable or superior to prior measurements; instead,
its significance is in advancing the capability of monitoring solar
irradiance variations on climate-relevant time scales and in improving
estimates of Earth energy balance, which the Sun initiates.
---------------------------------------------------------
Title: Fall 2010 Total Solar Irradiance Calibration Workshop
Authors: Morrill, J. S.; Socker, D. G.; Willson, R. C.; Kopp, G.
2010AGUFMGC21B0870M Altcode:
As part of a NASA-Sponsored program to understand the differences in
Total Solar Irradiance (TSI) results reported by various space-based
radiometers, the Naval Research Laboratory is hosting a Total Solar
Irradiance Calibration Workshop. This workshop is a follow-on meeting
to a similar workshop hosted by the National Institute for Standards
and Technology in 2005. These workshops have been attended by many of
the PI teams of the past and current TSI measuring instruments. The
discussions at these workshops have addressed calibration methods and
the numerous instrumental differences that need to be understood in
order to bring the complete ensemble of results onto a common scale. In
this talk we will present an overview of the NRL Calibration Workshop
which will include results of recent calibration studies at various
laboratories and have involved several TSI instruments.
---------------------------------------------------------
Title: Variability in SCIAMACHY Earth-Reflected Solar Spectral
Radiance: Guidance for Climate Benchmarking
Authors: Pilewskie, Peter; Roberts, Yolanda; Kindel, Bruce; Kopp, Greg
2010cosp...38...22P Altcode: 2010cosp.meet...22P
The difference between the solar radiation incident at the
top-of-the-atmosphere and that re-flected to space establishes
the infrared emission required for radiative equilibrium and thus
represents the most fundamental equation of climate. Detecting climate
change signatures in reflected solar radiance has been hindered by
instrument accuracy and stability, insufficient spectral coverage
and resolution, and inherent sampling limitations from low-Earth
orbit obser-vations. The primary goal of the Decadal Survey's Climate
Absolute Radiance and Refractivity Observatory (CLARREO) mission is
to obtain climate "benchmark" data records with sufficient accuracy
for identifying climate variability on decadal time scales and with
sufficient informa-tion content to attribute change to underlying
causality. Measurements of Earth-reflected solar spectral radiance
from the ESA SCanning Imaging Absorption SpectroMeter for Atmospheric
CHartographY (SCIAMACHY) have proven useful in defining a number of
requirements for future missions that will establish climate benchmark
data records. This paper presents results of CLARREO science definition
studies utilizing the variability in SCIAMACHY spectra over spatial
and temporal domains that can assist in defining the requirements of
an Earth-viewing shortwave spectrometer for climate benchmarking. These
same methods of analysis may also be applied to the detection of climate
trends, and examples using SCIAMACHY spectra illustrate this capability.
---------------------------------------------------------
Title: Total solar irradiance record accuracy and recent improvements
Authors: Kopp, Greg
2010cosp...38.1690K Altcode: 2010cosp.meet.1690K
The total solar irradiance (TSI) data record includes uninterrupted
measurements from over 10 spaceborne instruments spanning the last
31 years. Continuity of on-orbit measurements allows adjustments for
instrument offsets to create a TSI composite needed for estimating
solar influences on Earth's climate. Because climate sensitivities to
solar forcings are determined not only from direct TSI measurements over
recent 11-year solar cycles but also from reconstructions of historical
solar variability based on the recent measurements, the accuracy of
the TSI record is critical. This climate data record currently relies
on both instrument stability and measurement continuity, although
improvements in absolute accuracy via better instrument calibrations
and new test facilities promise to reduce this current reliance on
continuity. The Total Irradiance Monitor (TIM) is striving for improved
levels of absolute accuracy, and a new TSI calibration facility is
now able to validate the accuracy of modern instruments and diagnose
causes of offsets between different TSI instruments. The instrument
offsets are due to calibration errors. As of early 2010, none of the
on-orbit instruments have been calibrated end-to-end to the needed
accuracy levels. The new TSI Radiometer Facility (TRF) built for NASA's
Glory mission provides these new calibration capabilities. Via direct
optical power comparisons to a NIST-calibrated cryogenic radiometer,
this ground-based facility provides calibrations of a TSI instrument
much as the instrument is operated in space: under vacuum, at full solar
irradiance power levels, and with uniform incoming light for irradiance
measurements. Both the PICARD/PREMOS and the upcoming Glory/TIM
instruments have been tested in this new facility, helping improve the
absolute accuracy of the TSI data record and diagnose the causes of
existing instrument offsets. In addition to being benchmarked to this
new ground-based reference, the Glory/TIM and the future TSIS/TIMs are
intended to achieve levels of absolute accuracy that should reduce the
TSI record's reliance on measurement continuity. I will discuss the
climate-derived requirements for the levels of absolute accuracy and
instrument stability needed for TSI measurements and describe current
work that is underway to achieve these measurement requirements.
---------------------------------------------------------
Title: Solar Surface Magnetism and Irradiance on Time Scales from
Days to the 11-Year Cycle
Authors: Domingo, V.; Ermolli, I.; Fox, P.; Fröhlich, C.; Haberreiter,
M.; Krivova, N.; Kopp, G.; Schmutz, W.; Solanki, S. K.; Spruit, H. C.;
Unruh, Y.; Vögler, A.
2009SSRv..145..337D Altcode:
The uninterrupted measurement of the total solar irradiance during the
last three solar cycles and an increasing amount of solar spectral
irradiance measurements as well as solar imaging observations
(magnetograms and photometric data) have stimulated the development
of models attributing irradiance variations to solar surface
magnetism. Here we review the current status of solar irradiance
measurements and modelling efforts based on solar photospheric
magnetic fields. Thereby we restrict ourselves to the study of solar
variations from days to the solar cycle. Phenomenological models
of the solar atmosphere in combination with imaging observations of
solar electromagnetic radiation and measurements of the photospheric
magnetic field have reached high enough quality to show that a large
fraction (at least, about 80%) of the solar irradiance variability
can be explained by the radiative effects of the magnetic activity
present in the photosphere. Also, significant progress has been made
with magnetohydrodynamic simulations of convection that allow us to
relate the radiance of the photospheric magnetic structures to the
observations.
---------------------------------------------------------
Title: The Solar Radiation and Climate Experiment (SORCE): Measuring
the Sun's influence on climate from space
Authors: Harder, J.; Snow, M.; Kopp, G.; Fontenla, J.; Pilewskie,
P.; Richard, E.; Woods, T.
2009EGUGA..11.3317H Altcode:
The NASA Solar Radiation and Climate Experiment, launched in January
of 2003, is a suite of instruments that measures the variability of
both the Sun's total solar irradiance (TSI) and its solar spectral
irradiance (SSI) over the 110-2400 nm spectral range thereby accounting
for more the 97% of the sun's radiant output. The SORCE spectrometers
decompose the TSI signal into its spectral components, and the solar
cycle trends in the 300-2400 nm have been measured for the first
time. The SORCE instruments have revealed a number of important
findings that have significance to the earth-climate system. 1) The
Total Irradiance Monitor (TIM) measures the TSI with a precision of
about1.0 part per million (ppm) and very small degradation that is
correctable to about 10 ppm. Furthermore, recent laboratory studies
support the absolute calibration of the instrument's reported Solar
Cycle 23 solar minimum irradiance value of 1360.75 Wm-2, an important
finding for Earth radiation budget analyses. 2) The time series from
the Spectral Irradiance Monitor (SIM) shows that the observed TSI
trends are the sum of offsetting spectral irradiance trends rather
than the quasi-uniform change predicted from proxy/solar atmospheric
models. These observed spectral irradiance changes will enable more
realistic investigations of the mechanisms of climate responses to
solar forcing. 3) The Solar Stellar Irradiance Comparison Experiment
(SOLSTICE) is an ultraviolet spectrometer that was also onboard UARS
satellite; the combined missions have a continuous observational record
extending back to 1992 encompassing two solar minimum time periods. In
the FUV portion of the spectrum (112-180 nm), the SOLSTICE data shows
a lower spectral irradiance during the minimum of Solar Cycle 23 than
during the minimum period of Solar Cycle 22 by about 5%.
---------------------------------------------------------
Title: SORCE Solar Irradiance Data Products
Authors: Lindholm, D. M.; Pankratz, C. K.; Knapp, B. G.; Meisner,
R.; Fontenla, J.; Harder, J. W.; McClintock, W. E.; Kopp, G.; Snow,
M.; Woods, T. N.
2008AGUFMSM11B1623L Altcode:
The Laboratory for Atmospheric and Space Physics (LASP) at the
University of Colorado manages the SOlar Radiation and Climate
Experiment (SORCE) Science Data System. This data processing system
routinely produces Total Solar Irradiance (TSI) and Spectral Solar
Irradiance (SSI) data products, which are formulated using measurements
from the four primary instruments on board the SORCE spacecraft. The TIM
instrument provides measurements of the TSI, whereas the SIM, SOLSTICE,
and XPS instruments collectively provide measurements of the solar
irradiance spectrum from 1 nm to 2400 nm (excluding 31-115 nm, which
is measured by the SEE instrument on NASA's TIMED mission). Derived
products, such as the Magnesium II Core-to-Wing Index which can be
used for space weather applications, are also produced. The SORCE
Science Data System utilizes raw spacecraft and instrument telemetry,
calibration data, and other ancillary information to produce a
variety of solar irradiance data products that have been corrected
for all known instrumental and operational factors. Since launch of
the SORCE spacecraft in January 2003, science processing algorithms
have continued to mature, instrument calibrations (e.g. degradation
corrections) have improved, and regularly updated versions of data
products have been released. "Level 3" data products (time-averaged over
daily and six-hourly periods and/or spectrally re-sampled onto uniform
wavelength scales) are routinely produced and delivered to the public
via the SORCE web site (http://lasp.colorado.edu/sorce/data/), and
are archived at the Goddard Earth Sciences (GES) Data and Information
Services Center (DISC). Native resolution "Level 2" products are also
available for scientific studies. This poster provides an overview
of the SORCE data processing system, summarizes the present state of
the processing algorithms, describes the quality of the current SORCE
data products, provides details on how to access SORCE science data,
and presents future plans.
---------------------------------------------------------
Title: TSIS: The Total Solar Irradiance Sensor
Authors: Sparn, T.; Pilewskie, P.; Harder, J.; Kopp, G.; Richard,
E.; Fontenla, J.; Woods, T.
2008AGUFM.A51F0165S Altcode:
The Total Solar Irradiance Sensor (TSIS) is a dual-instrument
package that will acquire solar irradiance in the next decade on the
National Polar-orbiting Operational Environmental Satellite System
(NPOESS). Originally de-manifested during the 2006 NPOESS restructuring,
TSIS was restored following a decision by the NPOESS Executive Committee
earlier this year because of its critical role in determining the
natural forcings of the climate system and the high priority given it by
the 2007 Earth Science Decadal Survey. TSIS is comprised of the Total
Irradiance Monitor, or TIM, which measures the total solar irradiance
(TSI) that is incident at the boundaries of the atmosphere; and the
Spectral Irradiance Monitor, or SIM, which measures solar spectral
irradiance (SSI) from 200 nm to 2400 nm (96 percent of the TSI). The
TSIS TIM and SIM are heritage instruments to those currently flying
on the NASA Solar Irradiance and Climate Experiment (SORCE). Both were
selected as part of the TSIS because of their unprecedented measurement
accuracy and stability, and because both measurements are essential to
constraining the energy input to the climate system and interpreting the
response of climate to external forcing. This paper will describe those
attributes of TSIS which uniquely define its capability to continue the
30-year record of TSI and to extend the new 5-year record of SSI. The
role of the solar irradiance data record in the present climate state,
as well as in past and future climate change, will also be presented.
---------------------------------------------------------
Title: Spectral irradiance variations: comparison between observations
and the SATIRE model on solar rotation time scales
Authors: Unruh, Y. C.; Krivova, N. A.; Solanki, S. K.; Harder, J. W.;
Kopp, G.
2008A&A...486..311U Altcode: 2008arXiv0802.4178U
Aims: We test the reliability of the observed and calculated spectral
irradiance variations between 200 and 1600 nm over a time span of
three solar rotations in 2004. <BR />Methods: We compare our model
calculations to spectral irradiance observations taken with SORCE/SIM,
SoHO/VIRGO, and UARS/SUSIM. The calculations assume LTE and are based
on the SATIRE (Spectral And Total Irradiance REconstruction) model. We
analyse the variability as a function of wavelength and present time
series in a number of selected wavelength regions covering the UV to
the NIR. We also show the facular and spot contributions to the total
calculated variability. <BR />Results: In most wavelength regions,
the variability agrees well between all sets of observations and the
model calculations. The model does particularly well between 400 and
1300 nm, but fails below 220 nm, as well as for some of the strong NUV
lines. Our calculations clearly show the shift from faculae-dominated
variability in the NUV to spot-dominated variability above approximately
400 nm. We also discuss some of the remaining problems, such as the low
sensitivity of SUSIM and SORCE for wavelengths between approximately
310 and 350 nm, where currently the model calculations still provide
the best estimates of solar variability.
---------------------------------------------------------
Title: Solar Spectral Irradiance Variability in the Near Infrared
and Correlations to the Variability of Total Solar Irradiance During
the Declining Phase of Solar Cycle 23
Authors: Richard, E. C.; Harder, J. W.; Fontenla, J.; Pilewskie, P.;
Kopp, G.; Woods, T. N.
2007AGUFMGC31B0349R Altcode:
The Spectral Irradiance Monitor (SIM) as part of the NASA EOS SORCE
mission continuously monitors the solar spectral irradiance (SSI)
across the wavelength region spanning the ultraviolet, visible and
near infrared (a region encompassing >97% of the TSI measured by
the SORCE Total Irradiance Monitor, TIM). These are the first daily
measurements from space with the required precision to detect real
changes in SSI. The record of TSI measured from space tracks changes
in solar total energy output and establishes the baseline for energy
input for the Earth. Where this radiative energy is deposited into
the Earth system, how the climate responds to solar variability,
and the mechanisms of climate response, are determined by how
the incident solar radiation is distributed with wavelength, the
SSI. For the near IR region in particular, spectral decomposition of
the TSI variability provides TOA constraints on the direct input for
atmospheric heating simulations. We present here the first long-term,
continuous measurements of the near infrared variability of solar
spectral irradiance and establish quantitative correlations of near
infrared variability across the spectral region of the solar H minus
opacity minimum with TSI variability. The unprecedented precision of
the SIM near-infrared measurements provide a direct determination
of the wavelength dependence of the facular and sunspot contrasts
and serve to refine solar atmospheric models of the solar magnetic
features that produce irradiance variability in emission from the
deepest photospheric layers.
---------------------------------------------------------
Title: SORCE Solar Irradiance Data Products
Authors: Lindholm, D. M.; Pankratz, C. K.; Knapp, B. G.; Meisner,
R.; Fontenla, J.; Harder, J. W.; McClintock, W. E.; Kopp, G.; Snow,
M.; Woods, T. N.
2007AGUFMSH13A1105L Altcode:
The Laboratory for Atmospheric and Space Physics (LASP) at the
University of Colorado manages the SOlar Radiation and Climate
Experiment (SORCE) Science Data System. This data processing system
routinely produces Total Solar Irradiance (TSI) and Spectral Solar
Irradiance (SSI) data products, which are formulated using measurements
from the four primary instruments on board the SORCE spacecraft. The TIM
instrument provides measurements of the TSI, whereas the SIM, SOLSTICE,
and XPS instruments collectively provide measurements of the solar
irradiance spectrum from 1 nm to 2400 nm (excluding 31-115nm, which
is measured by the SEE instrument on NASA's TIMED mission). The SORCE
Science Data System utilizes raw spacecraft and instrument telemetry,
calibration data, and other ancillary information to produce a variety
of solar irradiance data products that have been corrected for all
known instrumental and operational factors. Since launch of the SORCE
spacecraft in January 2003, science processing algorithms have continued
to mature, and "Level 3" data products (time-averaged and/or spectrally
resampled onto uniform wavelength scales) are routinely being produced
and delivered to the public via the SORCE web site, and are archived at
the Goddard Earth Sciences (GES) Data and Information Services Center
(DISC, formerly DAAC). This poster provides an overview of the SORCE
data processing system, summarizes the present state of the processing
algorithms and future plans, describes the quality of the current SORCE
data products, and provides details on how to access SORCE science data.
---------------------------------------------------------
Title: Correlations Between Total Solar Irradiance and Spectral
Irradiances Using SORCE Measurements
Authors: Kopp, G.
2006AGUFMSH43A1504K Altcode:
The SOlar Radiation and Climate Experiment (SORCE) was launched
in January 2003 to measure both total solar irradiance (TSI) and
spectral solar irradiance (SSI). The available spectral irradiances
are contiguous from 115 nm to 1600 nm with nearly daily coverage,
providing useful inputs to climate models since the Earth's atmospheric
response is highly wavelength dependent. By correlating these relatively
recent and short-duration spectral irradiances with simultaneous SORCE
TSI measurements, the SSI may be linked to the nearly 3- decade long
TSI record. Extending this SSI proxy via the TSI record may provide
an estimate of historical spectral irradiances allowing comparisons
to past climate. I present results from these wavelength-dependent
correlations between SORCE TSI and SSI measurements.
---------------------------------------------------------
Title: Solar Irradiance Data for Space Weather from SORCE and
TIMED-SEE
Authors: Snow, M.; Woodraska, D.; McClintock, W. E.; Woods, T. N.;
Kopp, G.
2006AGUFMSA53A1352S Altcode:
The SOlar Radiation and Climate Experiment (SORCE) and Thermosphere
Ionosphere Mesosphere Energetics and Dynamics (TIMED) missions
produce many solar irradiance data products of interest to the
space weather community. The SOLar-STellar Irradiance Comparison
Experiment (SOLSTICE) and Solar EUV Experiment (SEE) measure solar
spectral irradiance below 300 nm, while the Total Irradiance Monitor
(TIM) detects the Total Solar Irradiance. Ultraviolet and extreme
ultraviolet solar spectral irradiances in defined bands are made
available shortly after spacecraft contacts every day. Six-hour
averages for the Magnesium II index and Total Solar Irradiance are
also produced on a daily basis. These datasets are available via ftp
for easy integration into the user's data stream. While these data
come from research experiments rather than operational satellites, we
have been able to make them reliably available for several years. The
SOLSTICE Mg II index is often used as a redundant data source in case
data from NOAA is unavailable. Additional space weather data products
are planned from the Solar Dynamics Observatory (SDO) EUV Variability
Experiement (EVE), which is scheduled for launch in August 2008.
---------------------------------------------------------
Title: Contributions of the solar ultraviolet irradiance to the
total solar irradiance during large flares
Authors: Woods, Thomas N.; Kopp, Greg; Chamberlin, Phillip C.
2006JGRA..11110S14W Altcode:
The solar X-ray radiation varies more than other wavelengths during
flares; thus solar X-ray irradiance measurements are relied upon for
detecting flare events as well as used to study flare parameters. There
is new information about the spectral and temporal variations of
flares using solar irradiance measurements from NASA's Solar Radiation
and Climate Experiment (SORCE) and the Thermosphere, Ionosphere,
Mesosphere, Energetics, and Dynamics (TIMED) missions. For one, the
improved measurement precision for the total solar irradiance (TSI)
measurements by the SORCE Total Irradiance Monitor (TIM) has enabled
the first detection of flares in the TSI. These flare observations
indicate a total flare energy that is about 105 times more than the
X-ray measurements in the 0.1-0.8 nm range. In addition, solar spectral
irradiance instruments aboard TIMED and SORCE have observed hundreds of
flare events in the 0.1 nm to 190 nm range. These solar ultraviolet
measurements show that the ultraviolet irradiance changes during
flares account for 50% or more of the flare variations seen in the TSI,
with most of the ultraviolet contribution coming from the ultraviolet
shortward of 14 nm. The remaining part of the flare energy is assumed
to come from the wavelengths longward of 190 nm, typically only needing
to be about 100 ppm increase for the largest flares. Another result
is that the flare variations in the TSI have a strong limb darkening
effect, whereby the flares near the limb indicate variations in the
TSI being almost entirely from the ultraviolet shortward of 14 nm.
---------------------------------------------------------
Title: SORCE Solar Irradiance Data Products
Authors: Pankratz, C. K.; Knapp, B. G.; Fontenla, J. M.; Rottman,
G. J.; Woods, T. N.; Harder, J. W.; Kopp, G.; McClintock, W. E.;
Snow, M.
2005AGUFMSM43B1219P Altcode:
The SORCE Science Data System produces Total Solar Irradiance
(TSI) and Spectral Solar Irradiance (SSI) data products on a daily
basis, which are formulated using measurements from the four primary
instruments on board the SORCE spacecraft. The TIM instrument provides
measurements of the TSI, whereas the SIM, SOLSTICE, and XPS instruments
collectively provide measurements of the solar irradiance spectrum from
1 nm to 2700 nm (excluding 31-115 nm, which is measured by the TIMED
SEE experiment). The Science Data System utilizes raw spacecraft and
instrument telemetry, calibration data, and other ancillary information
to produce a variety of data products that have been corrected for
all known instrumental and operational factors. Since launch of
the SORCE spacecraft in January 2003, science processing algorithms
have continued to mature, and "Level 3" data products are routinely
being produced and delivered to the public via the SORCE web site and
the Goddard Earth Sciences (GES) Distributed Active Archive Center
(DAAC). This poster provides an overview of the SORCE data processing
system, summarizes the present state of the processing algorithms and
future plans, describes the quality of the current SORCE data products,
and provides details on how to access SORCE science data. The NPOESS
TSIS instrument package will also include TIM and SIM instruments,
having direct flight heritage from the SORCE mission, and will produce
data products similar to those produced by the existing SORCE Science
Data System.
---------------------------------------------------------
Title: The Absolute Accuracy of Space-Borne TSI Instruments: A
Summary From the July 2005 TSI Accuracy Workshop
Authors: Kopp, G.; Butler, J. J.; Lawrence, G.
2005AGUFMSH33C..05K Altcode:
Space-borne measurements of the total solar irradiance (TSI) have
been continuous since 1978 due to the temporal overlap from multiple
instruments. Offsets between the several instruments contributing
to the data record exceed the stated uncertainties of many of the
instruments. To review the stated and assess the actual accuracies of
the instruments, a workshop was held at NIST, Gaithersburg in July 2005
with speakers representing 7 of the space-borne TSI instruments. This
workshop focused on two key areas of TSI measurement: 1) What is the
absolute accuracy of each instrument? 2) How stable is each instrument,
and thus how well can each track long-term changes in the TSI? We
summarize the results of the workshop addressing the first of these
questions, the absolute accuracy of the instruments. This is the
'Day 1' problem: after ground calibrations and launch, and prior to
degradation from solar exposure and the space environment, how well does
each instrument measure the true value of the TSI on an absolute scale?
---------------------------------------------------------
Title: The TSIS Sensors: Results and Instrument Analysis for the
SORCE SIM Instrument
Authors: Richard, E. C.; Harder, J. W.; Kopp, G.; Woods, T. N.
2005AGUFMSM51C..05R Altcode:
The SORCE (SOlar Radiation and Climate Experiment) SIM (Spectral
Irradiance Monitor) is a currently operating prism spectrometer
that measures the solar spectrum four times a day in the 200-2700
nm region with a wavelength dependent resolution of 1 - 33 nm. SIM
has been operational for 2.5 years and is now providing the first
continuous record of solar variability throughout the visible and near
infrared spectral regions and will continue this critical measurement
on the upcoming TSIS mission. To fulfill the EDR (Environmental
Data Record) for solar spectral irradiance, a number of in-flight
instrument re-calibrations must be performed to account for possible
instrument degradation processes that affect the pre-flight absolute
calibration. This presentation will describe the in-flight recalibration
steps currently used for SORCE and will be applied for TSIS, a summary
of the planned preflight calibration, and present the SORCE spectral
irradiance time series of solar spectral variability to demonstrate
the need for these in-flight and pre-flight calibrations.
---------------------------------------------------------
Title: The TSIS Sensors: Current SORCE Results and Progress Toward
NPOESS
Authors: Kopp, G.; Rottman, G.; Harder, J.; Richard, E.; Viereck, R.
2005AGUFMSM51C..04K Altcode:
The Total and Spectral Irradiance Sensor (TSIS) on the NPOESS is a
combination of two solar irradiance instruments to monitor the solar
energy incident at the top of the Earth's atmosphere. The first versions
of these instruments are currently operating on NASA's SOlar Radiation
and Climate Experiment (SORCE). The Total Irradiance Monitor (TIM)
measures total solar irradiance (TSI) with high accuracy and precision,
continuing a data record that has been uninterrupted since 1978. This
TSI record is used both to determine solar forcing on the Earth's
climate and to establish correlations with long duration proxies
of solar activity, allowing estimates of past solar influences on
the Earth. The Spectral Irradiance Monitor (SIM) measures the solar
spectral irradiance from 0.2 to 2.7 microns. SIM data provide spectral
resolution useful in determining the response of different layers in
the Earth's atmosphere to solar variations and in diagnosing the solar
causes of irradiance variations. A common pointing platform allows
the two instruments to monitor the Sun almost continually without
interfering with other NPOESS spacecraft operations. We present an
overview of the TSIS requirements and sensors, status of the current
SORCE measurements, progress on the NASA/Glory TIM (which continues
the TSI data record from SORCE to TSIS), and current progress on TSIS.
---------------------------------------------------------
Title: Contributions of the Solar Ultraviolet Irradiance to the
Total Solar Irradiance During Large Flares
Authors: Woods, T. N.; Kopp, G.
2005AGUFMSA33A..07W Altcode:
The TIMED satellite was launched in December 2001 and the SORCE
satellite was launched in January 2003. Since then the solar activity
has evolved from solar maximum conditions to moderately low activity
in 2005. The XUV Photometer System (XPS), aboard both TIMED and SORCE,
is measuring the solar soft X-ray (XUV) irradiance shortward of 34 nm
with 7-10 nm spectral resolution and the bright hydrogen emission at
121.5 nm. The XPS instrument is best known for observing over 200 flares
during the TIMED mission with its 3% solar observing duty cycle and over
800 flares during the SORCE mission with its 70% duty cycle. The XUV
radiation, being mostly from coronal emissions, varies more than other
wavelengths in the solar spectrum during a flare event, with each flare
lasting from minutes to hours. The XPS measurements indicate variations
by a factor of 50 for the largest flares during the October-November
2003 solar storm period and that the XUV variations can be as much
as 20% of the total flare energy as determined from the total solar
irradiance (TSI) measurements by the SORCE Total Irradiance Monitor
(TIM). The flare variations of the solar XUV irradiance and TSI will
be discussed in the context of the TIMED and SORCE missions and their
relationship to the GOES X-ray flare measurements.
---------------------------------------------------------
Title: The spectral composition of TSI as measured by the SORCE SIM
solar spectral radiometer
Authors: Harder, J. W.; Fontenla, J.; Kopp, G.; Richard, E.; Woods, T.
2005AGUFMSH41A1113H Altcode:
The SORCE (Solar Radiation and Climate Experiment) SIM (Spectral
Irradiance Monitor) instrument is a satellite-borne prism spectrometer
that measures the solar spectrum from 200-2700 nm with a cadence of
at least 2 spectra per day and a wavelength dependent resolution
of 1-33 nm. This instrument provides the temporal evolution of
solar irradiance in the ultraviolet, visible, and infrared spectral
regions. At some wavelengths in the ultraviolet, the SIM measurements
exhibit variations similar to the Mg II core-to-wing ratio, and in the
visible and IR they show similarities to the total solar irradiance
(TSI) record, but with differing wavelength dependent amplitudes,
phases, and shapes. Furthermore, the observed TSI variations can be
examined in the context of the integral of the spectral irradiance
over discrete spectral bands in the 200-1600 nm region showing the
spectral contributions of solar active regions. Further insight into
the solar variability observed by the SIM can be gained from analyzing
the distribution of solar features as measured by the Precision Solar
Photometric Telescope in conjunction with spectral decomposition (ApJ,
1999, 518, 480).
---------------------------------------------------------
Title: The Total Irradiance Monitor (TIM): Instrument Design
Authors: Kopp, Greg; Lawrence, George
2005SoPh..230...91K Altcode:
The Total Irradiance Monitor (TIM) instrument is designed to
measure total solar irradiance with an absolute accuracy of 100
parts per million. Four electrical substitution radiometers behind
precision apertures measure input radiant power while providing
redundancy. Duty cycling the use of the radiometers tracks degradation
of the nickel-phosphorous absorptive black radiometer interiors
caused by solar exposure. Phase sensitive detection at the shutter
frequency reduces noise and simplifies the estimate of the radiometer's
equivalence ratio. An as-designed uncertainty budget estimates the
instrument's accuracy goal. The TIM measurement equation defines the
conversion from measured signal to solar irradiance.
---------------------------------------------------------
Title: The Total Irradiance Monitor (TIM): Instrument Calibration
Authors: Kopp, Greg; Heuerman, Karl; Lawrence, George
2005SoPh..230..111K Altcode:
The calibrations of the SORCE Total Irradiance Monitor (TIM) are
detailed and compared against the designed uncertainty budget. Several
primary calibrations were accomplished in the laboratory before launch,
including the aperture area, applied radiometer power, and radiometer
absorption efficiency. Other parameters are calibrated or tracked on
orbit, including the electronic servo system gain, the radiometer
sensitivity to background thermal emission, and the degradation of
radiometer efficiency. The as-designed uncertainty budget is refined
with knowledge from the on-orbit performance.
---------------------------------------------------------
Title: SORCE Contributions to New Understanding of Global Change
and Solar Variability
Authors: Lean, Judith; Rottman, Gary; Harder, Jerald; Kopp, Greg
2005SoPh..230...27L Altcode:
An array of empirical evidence in the space era, and in the past,
suggests that climate responds to solar activity. The response
mechanisms are thought to be some combination of direct surface heating,
indirect processes involving UV radiation and the stratosphere, and
modulation of internal climate system oscillations. A quantitative
physical description is, as yet, lacking to explain the empirical
evidence in terms of the known magnitude of solar radiative output
changes and of climate sensitivity to these changes. Reproducing
solar-induced decadal climate change requires faster and larger
responses than general circulation models allow. Nor is the indirect
climatic impact of solar-induced stratospheric change adequately
understood, in part because of uncertainties in the vertical coupling
of the stratosphere and troposphere. Accounting for solar effects
on pre-industrial surface temperatures requires larger irradiance
variations than present in the contemporary database, but evidence
for significant secular irradiance change is ambiguous. Essential
for future progress are reliable, extended observations of the solar
radiative output changes that produce climate forcing. Twenty-five
years after the beginning of continuous monitoring of the Sun's total
radiative output, the Solar Radiation and Climate Experiment (SORCE)
commences a new generation of solar irradiance measurements with much
expanded capabilities. Relative to historical solar observations SORCE
monitors both total and spectral irradiance with significantly reduced
uncertainty and increased repeatability, especially on long time
scales. Spectral coverage expands beyond UV wavelengths to encompass
the visible and near-IR regions that dominate the Sun's radiative
output. The space-based irradiance record, augmented now with the
spectrum of the changes, facilitates improved characterization
of magnetic sources of irradiance variability, and the detection
of additional mechanisms. This understanding provides a scientific
basis for estimating past and future irradiance variations, needed
for detecting and predicting climate change.
---------------------------------------------------------
Title: The Total Irradiance Monitor (TIM): Science Results
Authors: Kopp, Greg; Lawrence, George; Rottman, Gary
2005SoPh..230..129K Altcode:
The solar observations from the Total Irradiance Monitor (TIM)
are discussed since the SOlar Radiation and Climate Experiment
(SORCE) launch in January 2003. The TIM measurements clearly show
the background disk-integrated solar oscillations of generally
less than 50 parts per million (ppm) amplitude over the ∼2 ppm
instrument noise level. The total solar irradiance (TSI) from the
TIM is about 1361 W/m<SUP>2</SUP>, or 4-5 W/m<SUP>2</SUP> lower than
that measured by other current TSI instruments. This difference is
not considered an instrument or calibration error. Comparisons with
other instruments show excellent agreement of solar variability on a
relative scale. The TIM observed the Sun during the extreme activity
period extending from late October to early November 2003. During this
period, the instrument recorded both the largest short-term decrease
in the 25-year TSI record and also the first definitive detection
of a solar flare in TSI, from which an integrated energy of roughly
(6± 3)×10<SUP>32</SUP> ergs from the 28 October 2003 X17 flare is
estimated. The TIM has also recorded two planets transiting the Sun,
although only the Venus transit on 8 June 2004 was definitive.
---------------------------------------------------------
Title: SORCE Solar Irradiance Data Products
Authors: Pankratz, C. K.; Knapp, B. G.; Fontenla, J. M.; Rottman,
G. J.; Woods, T. N.; Harder, J. W.; Kopp, G.; McClintock, W. E.;
Snow, M.
2005AGUSMSH51B..03P Altcode:
The SORCE Science Data System produces Total Solar Irradiance
(TSI) and Spectral Solar Irradiance (SSI) data products on a daily
basis, which are formulated using measurements from the four primary
instruments on board the SORCE spacecraft. The TIM instrument provides
measurements of the TSI, whereas the SIM, SOLSTICE, and XPS instruments
collectively provide measurements of the solar irradiance spectrum from
1 nm to 3000 nm (excluding 31-115nm, which is covered by the TIMED
SEE experiment). The Science Data System utilizes raw spacecraft and
instrument telemetry, calibration data, and other ancillary information
to produce a variety of data products that have been corrected for
all known instrumental and operational factors. Since launch of
the SORCE spacecraft in January 2003, science processing algorithms
have continued to mature, and "Level 3" data products are routinely
being produced and delivered to the public via the SORCE web site and
the Goddard Earth Sciences (GES) Distributed Active Archive Center
(DAAC). This poster provides an overview of the SORCE data processing
system, summarizes the present state of the processing algorithms and
the quality of the current SORCE data products, and provides details
on how to access SORCE science data.
---------------------------------------------------------
Title: A Comparison of Total Solar Irradiance to the Mg II Index
Based on SORCE Measurements
Authors: Kopp, G.; Snow, M.; McClintock, W.; Woods, T.
2005AGUSMSH23B..04K Altcode:
The reconstruction of the total solar irradiance (TSI) over the
long-term often uses sunspot area and a faculae proxy such as the Mg
II core-to-wing index (Mg index). With interest in validating this
approach, we compare the Mg index to TSI measurements using data from
NASA's SOlar Radiation and Climate Experiment (SORCE). The SORCE carries
four solar irradiance instruments that have been monitoring the Sun
since early 2003. The Total Irradiance Monitor (TIM) measures the TSI
with unprecedented stability and low noise during the daytime portion
of each spacecraft orbit with a time cadence of 100 seconds. The
SOLar STellar Irradiance Comparison Experiment (SOLSTICE) measures
solar spectral irradiance from 115 to 320 nm, having 0.1 nm spectral
resolution at the Mg II lines near 280 nm. The Mg II lines are scanned
approximately seven times each day, and the Mg index provides a good
indicator of chromospheric activity. We compare the SOLSTICE Mg II
core-to-wing index to TIM TSI measurements, giving advantages over
previous comparisons including simultaneity, low noise, and high
spectral resolution for the Mg II lines.
---------------------------------------------------------
Title: TIM Degradation Rates and Possibilities of Measuring Secular
TSI Changes
Authors: Kopp, G.; Lawrence, G.; Rottman, G.
2004AGUFMSH53A0302K Altcode:
We present the on-orbit degradation measured on the Total Irradiance
Monitor (TIM), a total solar irradiance (TSI) monitoring instrument on
NASA's SOlar Radiation and Climate Experiment (SORCE). The monitored
degradation to date is extremely small (50 ppm/yr) with an uncertainty
of 10 ppm/yr. We discuss the possibilities of accurately measuring
secular changes in TSI using instruments with comparable degradation
rates.
---------------------------------------------------------
Title: GOMOS Ozone Profile Validation Using Data From Ground-Based
and Balloon-Sonde Measurements
Authors: Meijer, Y. J.; Swart, D. P. J.; Allaart, M.; Andersen,
S. B.; Bodeker, G.; Boyd, I.; Braathen, G.; Calisesi, Y.; Claude,
H.; Dorokhov, V.; von der Gathen, P.; Gil, M.; Godin-Beekmann, S.;
Goutail, F.; Hansen, G.; Karpetchko, A.; Keckhut, P.; Kelder, H. M.;
Koelemeijer, R.; Kois, B.; Koopman, R. M.; Lambert, J. -C.; Leblanc,
T.; McDermid, I. S.; Pal, S.; Kopp, G.; Schets, H.; Stübi, R.;
Suortti, T.; Visconti, G.; Yela, M.
2004ESASP.562E..61M Altcode: 2004acve.conf...61M
One of the nine instruments on-board the polar-orbiting environmental
satellite ENVISAT is the Global Ozone Monitoring by Occultation of Stars
(GOMOS) instrument. This paper presents validation results of GOMOS
ozone profiles (v6.0a) from comparisons to microwave radiometer, balloon
ozonesonde and lidar measurements worldwide. Thirty-one instruments/
launch-sites at twenty-five stations ranging from the Arctic to the
Antarctic joined in this activity. We identified 3,713 useful collocated
observations that were performed within an 800-km radius and a maximum
20hours time difference of a satellite observation, for the period June
2002 and March 2003. These collocated profiles were compared and the
results were analyzed for possible dependencies on several geophysical
(e.g., latitude) and GOMOS observational (e.g., star characteristics)
parameters. In a dark atmospheric limb the GOMOS data agree very well
with the correlative data and between 20- to 61-km altitude their
differences only show a small (2.5%) insignificant negative bias with a
standard deviation of about 14%. This conclusion is demonstrated to be
independent of the star temperature and magnitude, and the latitudinal
region of the GOMOS observation
---------------------------------------------------------
Title: Validation of SCIAMACHY Ozone Column Densities and Profiles
Using Ground-Based FTIR and Millimeter Wave Measurements
Authors: Kopp, G.; Blumenstock, Th.; Brinksma, E.; Eskes, H.;
Griesfeller, A.; Hase, F.; Hochschild, G.; Kramer, I.; Mikuteit, S.;
Raffalski, U.; van der A, R.
2004ESASP.562E..35K Altcode: 2004acve.conf...35K
Ground-based FTIR and millimeter wave measurements of the Institute of
Meteorology and Climate Research (IMK), Forschungszentrum Karlsruhe,
and the Swedish Institute of Space Physics (IRF) are used for
validation of SCIAMACHY ozone measurements. FTIR and millimeter wave
measurements used for this study were routinely carried out between
2002 and 2004 at IRF at Kiruna, Sweden. In addition IMK carried
out millimeter wave measurements on Mount Zugspitze in the Alps in
2003. SCIAMACHY level 2 NRT-products of 2002 are only validated by
FTIR data since millimeter wave observations started in late 2002 when
SCIAMACHY data were unavailable. For the years 2003 and early 2004
total ozone column abundances retrieved with the TOSOMI algorithm of
the Royal Netherlands Meteorological Institute (Koninklijk Nederlands
Meteorologisch Instituut, KNMI) are validated by the FTIR and microwave
measurements. Finally, ozone limb profiles between July and November
2002 taken from the current SCIA Level 2 Off-Line masterset are
validated by the FTIR measurements at Kiruna
---------------------------------------------------------
Title: SCIMACHY Ozone Profile Validation
Authors: Brinksma, E. J.; Piters, A. J. M.; Boyd, L. S.; Parrish,
A.; Bracher, A.; von Savigny, C.; Bramstedt, K.; Schmoltner, A. -M.;
Taha, G.; Hilsenrath, E.; Blumenstock, T.; Kopp, G.; Mikuteit, S.;
Fix, A.; Meijer, Y. J.; Swart, D. P. J.; Bodeker, G. E.; McDermid,
I. S.; Leblanc, T.
2004ESASP.562E..15B Altcode: 2004acve.conf...15B
No abstract at ADS
---------------------------------------------------------
Title: Validation of MIPAS and SCIAMACHY Data by Ground-Based
Spectroscopy at Kiruna, Sweden, and Izana, Tenerife Island (AOID-191)
Authors: Blumenstock, T.; Mikuteit, S.; Griesfeller, A.; Hase,
F.; Kopp, G.; Kramer, I.; Schneider, M.; Fischer, H.; Gil, M.;
Moreta, J. R.; Navarro Coma, M.; Raffalski, U.; Cuevas, E.; Dix, B.;
Schwarz, G.
2004ESASP.562E..49B Altcode: 2004acve.conf...49B
Within this ENVISAT validation project [AOID-191] ground-based
measurements of different techniques have been performed at Kiruna in
the Arctic and on Tenerife Island in the subtropics. These ground-based
data were used to validate SCIAMACHY and MIPAS data. Using MIPAS 4.61
O3 profiles on a pressure scale and degrading their vertical resolution
to that of the FTIR profiles a good agreement is demonstrated. The
precision of FTIR O3 profiles is about 10 %. The differences between
MIPAS and FTIR are within the combined error bar. MIPAS 4.61 HNO3
profiles differ about 10 to 15 % for altitudes above 15 km. The
corresponding column amounts differ by 8.2 +/- 7.0 %. These differences
can be explained by a scaling factor in the spectroscopic data base for
HNO3 which has been applied in version 4.61. SCIAMACHY O3 and NO2 column
amounts of versions 5.01 agree much better as compared to previous
versions: The difference of SCIAMACHY O3 column amounts is about 8 %
when compared to FTIR data from Kiruna and about 2 % when compared with
DOAS data from Izaña, respectively. The difference of SCIAMACHY NO2
column amounts to Izaña DOAS data is about 9 %. Furthermore, O3 limb
profiles from SCIAMACHY have been compared for the first time. The mean
differences are up to 20%. However, shifting the SCIAMACHY profiles by
+1.5 km reduces the discrepancies significantly. Then the mean relative
difference is smaller than 10% for all altitude levels between 10 and
35 km. This shift is consistent with the erroneous height assignment
of MIPAS profiles
---------------------------------------------------------
Title: Solar irradiance variability during the October 2003 solar
storm period
Authors: Woods, Thomas N.; Eparvier, Francis G.; Fontenla, Juan;
Harder, Jerald; Kopp, Greg; McClintock, William E.; Rottman, Gary;
Smiley, Byron; Snow, Martin
2004GeoRL..3110802W Altcode:
The extraordinary solar storms between 18 October 2003 and 5 November
2003 include over 140 flares, primarily from two different large
sunspot groups. There were 11 large X-class flares during this period,
including an X17 flare on 28 October 2003 and an X28 flare on 4 November
2003. The X28 flare is the largest flare since GOES began its solar
X-ray measurements in 1976. The solar (full-disk) irradiance during
these flares was observed by the instruments aboard the NASA Solar
Radiation and Climate Experiment (SORCE) spacecraft and the NASA
Thermosphere, Ionosphere, Mesosphere, Energetics, and Dynamics (TIMED)
spacecraft. The total solar irradiance (TSI) dropped by unprecedented
0.34% during this period due to the dark, large sunspots. In addition,
the TSI increased by 270 ppm during the X17 (4B optical) flare on 28
October, the first definitive measurement of a TSI flare event. The
ultraviolet (UV) variations for this X17 flare range from a factor
of about 50 shortward of 10 nm to about 10% for the Mg II 280 nm
emission. One interesting result for the UV flare variations is that
the broad wings of the H I Lyman-α (121.6 nm) emission increased by
more than a factor of 2 during the X17 flare while the core of the
Lyman-α emission only increased by 20%. Another interesting result is
the time profile of the Si III 120.6 nm emission, which shows a sharp
1-minute long increase by a factor of 17 during the impulsive phase.
---------------------------------------------------------
Title: Total Solar Irradiance Observations of the Oct./Nov. 2003
Solar Flares
Authors: Kopp, G.; Lawrence, G. M.; Rottman, G.; Woods, T.
2004AAS...204.0215K Altcode: 2004BAAS...36..669K
We report on the first definitive observation of a solar flare in
total solar irradiance (TSI) and on TSI observations of several other
flares during the active Oct./Nov. time period. Solar flares are most
prominent in EUV or X-ray wavelengths, since they release significant
energy in these spectral regions where the Sun itself has a relatively
low background. Despite their high energies, flares are minuscule
compared to the entire energy output of the Sun, and thus cause very
little change in TSI. Indeed, in 25 years of space-based irradiance
monitoring prior to October 2003, no previous solar flare had been
measured in TSI. <P />The Oct. 28, 2003 X17 flare was measured by the
Total Irradiance Monitor (TIM) on NASA's SORCE. The TIM measures power
across the entire solar spectrum, integrating X-ray to far infrared
wavelengths. TIM data show a sudden increase of almost 270 parts
per million slightly preceding the flare's soft X-ray peak at 11:10
UT. The TSI signature is similar to hard X-ray emissions in that it
roughly coincides with the maximum rate of change of the soft X-ray
emission. <P />The TSI measurement provides the spectrally integrated
flare energy. We estimate the Oct. 28 flare had total energy exceeding
4.6e25 Joules. Preliminary estimates of the flare energy at wavelengths
shorter than 200 nm, based on solar EUV measurements from other SORCE
instruments and from an instrument on NASA's TIMED mission, only account
for 23% of this energy, meaning the majority of the flare's energy was
at longer wavelengths. This, combined with the timing of the flare in
TSI, may indicate that portions of the visible and UV included in TSI
also respond to the initiation phase of the flare. <P />We appreciate
the support of NASA for this work.
---------------------------------------------------------
Title: Remarkable Low Temperature Emission of the 4 November 2003
Limb Flare
Authors: Leibacher, J. W.; Harvey, J. W.; Kopp, G.; Hudson, H.;
GONG Team
2004AAS...204.0213L Altcode: 2004BAAS...36..669L
Strong (> 1.5 times normal intensity) continuum and photospheric line
emission of the 4 November 2003 X28 flare was recorded simultaneously
by three widely separated GONG instruments. Emission was seen from
on the disk to > 20" above the limb for nearly one hour, likely
making this event the longest duration white light flare observed
to date. GONG observations are one-minute duration integrations of
intensity averaged across a Lyot filter bandpass of about 90 pm FWHM
centered on the Ni I line at 676.8 nm with 2.5" instrument pixel
size. Spatial resolution is limited by diffraction and seeing to
greater than 5". Additional measurements include the Doppler shift and
strength of the spectrum line. These latter measurements indicate that
continuum and line emission contributed about equally to the observed
intensity signal. Light curves and images of the flare show a notable
two-kernel disk event starting at about 19:33 UTC followed by a much
stronger event that peaked at about 19:44. Rare, white-light prominences
were visible above the limb after 19:34. Comparison of total solar
irradiance measurements from the TIM instrument on board the SORCE
spacecraft with full-disk integrated GONG intensities shows the global
five-minute oscillation and the white light flare. The latter is much
weaker in the GONG data, suggesting that most of the TIM flare signal
arises from other, most likely shorter, wavelengths. <P />This work
utilizes data obtained by the Global Oscillation Network Group (GONG)
Program, managed by the National Solar Observatory, which is operated
by AURA, Inc. under a cooperative agreement with the National Science
Foundation. SORCE is supported by NASA NAS5-97045
---------------------------------------------------------
Title: Irradiance Observations of the October 28, 2003 X-17 Flare
Authors: Rottman, G.; Woods, T.; Kopp, G.; McClintock, W.; Snow, M.;
Fontenla, J.; Harder, J.
2004AGUSMSH31B..02R Altcode:
The Solar Radiation and Climate Experiment, SORCE, carries four
instruments that measure solar irradiance -- both total solar
irradiance, TSI, and spectral irradiance from soft X-rays, ultraviolet,
visible and near infrared. During the X-17 flare at 11:00 UT on October
28, 2003 the SORCE instruments were in ideal configurations to record
increases in TSI and at most observed wavelengths. The X-ray and UV
irradiance originating in the transition region and corona increased
by factors as large as fifty. This large flare also provided the first
measurement of an increase in TSI, a unique measurement that places an
important new constraint on the energy release during the flare. This
report is a survey and interpretation of the irradiance variations
observed during this X-17 flare.
---------------------------------------------------------
Title: Total irradiance monitor design and on-orbit functionality
Authors: Kopp, Greg; Lawrence, George; Rottman, Gary
2004SPIE.5171...14K Altcode:
The solar Total Irradiance Monitor (TIM) on NASA's SORCE mission began
taking data in early 2003. This instrument continues the 25-year
record of space-borne, total solar irradiance (TSI) measurements,
with improved precision from its new technologies and calibration
methods. We present an overview of the TIM instrument, including the
design features enabling its high precision, and we present preliminary
on-orbit TSI data.
---------------------------------------------------------
Title: What is the Accuracy of the Total Irradiance Monitor?
Authors: Kopp, G. A.; Lawrence, G.; Rottman, G.
2003AGUFMSH31C..07K Altcode:
The Total Irradiance Monitor (TIM) on NASA's SOlar Radiation and Climate
Experiment (SORCE) is the most recently launched instrument to monitor
the total solar irradiance (TSI). We present results from the first of
the TIM's five years of operations and discuss the current knowledge of
the instrument's accuracy. To date, we find the four instrument channels
in good agreement and extremely robust against solar exposure. Such
instrument characterizations and measurement accuracies influence the
observational scenarios appropriate for determining long-term solar
variability, and currently favor overlapping measurements of very
stable TSI-monitoring instruments.
---------------------------------------------------------
Title: Liquid crystal intensity modulator for simulating planetary
transits
Authors: Kopp, Greg
2003SPIE.5170..229K Altcode:
I describe a liquid crystal intensity modulator designed to achieve
<10 parts per million (ppm) modulation to simulate a planetary
transit like those required for ground testing of NASA's Kepler
mission. The design uses a nematic liquid crystal as a variable retarder
aligned between two linear polarizers, with the retardance values and
the alignment chosen to provide low sensitivity of transmitted intensity
to input liquid crystal voltage variations. Modulator test results
give intensity fluctuations of a few ppm from millivolt modulations
about the input 8 V baseline voltage.
---------------------------------------------------------
Title: Phase Sensitive Detection for the SORCE Total Irradiance
Monitor
Authors: Kopp, G.; Lawrence, G.; Rottman, G.; Woods, T.
2002AGUFMSH52A0496K Altcode:
The Total Irradiance Monitor (TIM) on the SOlar Radiation and
Climate Experiment (SORCE) will measure the total solar irradiance
(TSI). The TIM will report four TSI measurements daily, continuing
the current 24-year record of solar irradiance through SORCE's goal
5-year mission life. This instrument was designed to achieve a relative
standard uncertainty (1 σ precision) of 100 parts per million (ppm)
and a precision and long-term uncertainty of 10 ppm/year. The major
innovation the TIM brings to spaceborne TSI measurements is phase
sensitive detection. This new instrument was designed from the ground
up with the primary consideration being low-noise performance at the
shutter fundamental, minimizing parasitic effects at and in-phase
with the instrument's shutter. The DSP-controlled thermal balance and
this phase sensitive detection method reduce sensitivity to thermal
fluctuations and noise, enabling the instrument's high precision. We
describe in detail here the phase sensitive detection algorithm used
for the TIM.
---------------------------------------------------------
Title: A summary of spacecraft measurements of total solar irradiance
Authors: Kopp, G.; Lawrence, G.; Rottman, G.
2002cosp...34E.694K Altcode: 2002cosp.meetE.694K
The mean total solar irradiance (TSI) varies about 0.1% over a solar
cycle, with 0.3% variability on time scales of a few weeks due to
active regions on the Sun. Accurate measurements of TSI from above
the Earth's atmosphere have been contiguous since 1978. Each of
the dozen instruments contributing a TSI time series to this data
set shows high sensitivity, detecting small changes in the Sun's
relative output. Absolute accuracy is less precise, giving offsets
between the instruments that are in some cases greater than the level
of solar variability. Long-term trends in the solar irradiance are
difficult to determine but tantalizingly close with the instruments'
measurement accuracies and with the two solar cycles of measurements
now available. We will summarize the spaceborne TSI measurements
and the results obtained from these several missions. We discuss the
relative and absolute instrument accuracies, leading to the observing
time lengths needed for detecting trends in the solar irradiance. We
will mention future missions that will continue the TSI data set and
discuss their expected accuracies.
---------------------------------------------------------
Title: SORCE - Continuing Measurements of Solar Irradiance
Authors: Kopp, G.; Rottman, G.; Woods, T.; Harder, J.; Lawrence, G.;
McClintock, B.; Adda, M.
2001AGUFM.A51E0085K Altcode:
The NASA/EOS Solar Radiation and Climate Experiment (SORCE) will measure
the total and the spectral irradiance from the Sun, continuing the solar
data record from the Upper Atmosphere Research Satellite (UARS). Four
SORCE instruments provide irradiance measurements at wavelengths from 1
nm to longer than 2000 nm. The Total Irradiance Monitor (TIM) measures
total solar irradiance (TSI), similar to the UARS/ACRIM instrument. The
TIM will achieve a relative standard uncertainty (1 σ precision)
of 100 parts per million (ppm), continuing the 23-year record of TSI
measurements. SORCE's two SOLar STellar Irradiance Comparison Experiment
(SOLSTICE) instruments are nearly identical to the SOLSTICE flown on
UARS. These grating spectrometers monitor the more highly-variable
solar ultraviolet irradiance over the wavelength range 120 to 300
nm with a 2 to 5% absolute uncertainty and a capability of making
relative solar variability measurements with an accuracy of 0.5%
by using stable, blue stars for in-flight calibration. The Spectral
Irradiance Monitor (SIM) is a new prism spectrometer providing the
first continuous solar spectral irradiance measurements from 200 to
2000 nm with 300 ppm uncertainty. The XUV Photometer System (XPS)
covers 1 to 35 nm using 9 spectral bandpass filters to measure the
large solar irradiance variations in the extreme ultraviolet with a
~20% accuracy. Launching in July of 2002 with a mission life goal of 5
years, SORCE will extend the UARS solar irradiance database in time as
well as spectral region. SORCE data will be available via NASA/GSFC's
Distributed Active Archive Center (DAAC) as well as from LASP's web site
(http://lasp.colorado.edu/sorce).
---------------------------------------------------------
Title: SORCE - The Solar Radiation and Climate Experiment
Authors: Kopp, G.; Rottman, G.; Harder, J.; Lawrence, G.; McClintock,
B.; Woods, T.
2001AGUSM..SH52A08K Altcode:
The NASA/EOS Solar Radiation and Climate Experiment (SORCE) will
measure the total and the spectral irradiance from the Sun, providing
inputs for understanding the Earth's climate. Four instruments
provide irradiance measurements at wavelengths from 1 nm to longer
than 2000 nm as follows: The Total Irradiance Monitor (TIM) measures
total solar irradiance (TSI) to a relative standard uncertainty (1 σ
precision) of 100 parts per million (ppm). The TIM will continue the
current 22-year record of solar irradiance measurements using a modern
phase-sensitive electronics design. The Spectral Irradiance Monitor
(SIM) provides the first continuous spectral irradiance measurements
from 200 to 2000 nm. This prism spectrometer will achieve 300 ppm
uncertainty and a spectral resolution ranging from 0.2 to 30 nm. The
Solar Stellar Irradiance Comparison Experiment (SOLSTICE) monitors the
more highly-variable solar ultraviolet irradiance with a ~5% uncertainty
over the wavelength range 120 to 300 nm. This grating spectrometer has
0.1 to 0.2 nm spectral resolution, and uses measurements of stable,
blue stars for in-flight calibration. This SORCE instrument continues
the data record from the Upper Atmospheric Research Satellite's
SOLSTICE. The XUV Photometer System (XPS) covers 1 to 35 nm using
9 spectral bandpass filters to measure the large solar irradiance
variations in the extreme ultraviolet with a ~20% accuracy. A nearly
identical instrument launches on the Thermosphere Ionosphere Mesosphere
Energetics and Dynamics (TIMED) mission in August 2001. SORCE will be
launched on a Pegasus XL into a low Earth orbit in July of 2002 with a
mission life goal of 5 years. Total and spectral irradiance data will
be available via NASA/GSFC's Distributed Active Archive Center (DAAC)
as well as from LASP's web site (http://lasp.colorado.edu/sorce).
---------------------------------------------------------
Title: Optical design for Terrestrial Planet Finder
Authors: Noecker, M. C.; Leitch, James W.; Kopp, Greg A.; McComas,
Brian K.
1999SPIE.3779...40N Altcode:
We describe the features of the optical system for Terrestrial Planet
Finder, a space-based, cryogenic interferometer for direct detection
of Earth-type planets around nearby stars. Destructive interference
in a stellar interferometer suppresses stellar glare by a factor
of several thousand or more, and phase chopping distinguishes planet
light from symmetric backgrounds. The mid-IR is favorable for detecting
planetary emission relative to that from the star, and this spectral
region also offers important molecular signatures indicative of key
atmospheric gases.
---------------------------------------------------------
Title: The vertical distribution of ClO at Ny-Ålesund during
March 1997
Authors: Ruhnke, R.; Kouker, W.; Reddmann, Th.; Berg, H.; Hochschild,
G.; Kopp, G.; Krupa, R.; Kuntz, M.
1999GeoRL..26..839R Altcode:
Results of the Karlsruhe Simulation Model of the Middle Atmosphere
(KASIMA) are compared with vertical ClO profiles measured by the
ground-based Millimeter Wave Radiometer MIRA2 inside the vortex
during March 1997 at Ny-Ålesund. The influence of the OH + ClO and
HO<SUB>2</SUB> + ClO reaction branching ratio and of the absorption
cross section of Cl<SUB>2</SUB>O<SUB>2</SUB> on the calculated mixing
ratios of ClO and ozone has been investigated. In the upper stratosphere
the ClO mixing ratio is reduced by 90% by using a minor channel of
the OH + ClO reaction with a branching ratio of 0.07. A temperature
dependent minor channel of the HO<SUB>2</SUB> + ClO reaction reduces
the upper stratospheric ClO mixing ratio by 22%. Different absorption
spectra of Cl<SUB>2</SUB>O<SUB>2</SUB> alter the ClO mixing ratios up
to 12% at noon at 20 km. This causes differences of 15% in the ozone
loss during winter.
---------------------------------------------------------
Title: Optical design for Terrestrial Planet Finder.
Authors: Noecker, M. C.; Kopp, G.; Leitch, J.; McComas, B.
1999aero....4...59N Altcode:
The authors describe the features of the optical system for
the Terrestrial Planet Finder, a space-based, cryogenic (35K)
interferometer for direct detection of Earth-type planets around nearby
stars. Interferometric nulling suppresses stellar glare by a factor
of several thousand or more, and phase chopping distinguishes planet
light from the symmetric background. The mid-infrared (7 - 20 μm)
is favorable for detecting planetary emission relative to that from
the star, and this spectral region also offers important molecular
signatures indicative of key atmospheric gases.
---------------------------------------------------------
Title: Outline of an optical design for Terrestrial Planet Finder
Authors: Noecker, Charley; McComas, Brian K.; Kopp, Greg A.
1998SPIE.3356..641N Altcode:
A nulling interferometer for direct detection and spectral studies
of the light from extra-solar planets would face daunting technical
challenges. We outline a candidate optical architecture, discussing the
major challenges in handling the starlight and controlling the optics
to produce a deep on-axis null with high transmission a fraction of
an arcsecond away.
---------------------------------------------------------
Title: Laser metrology for space interferometry
Authors: Leitch, James W.; Kopp, Greg A.; Noecker, Charley
1998SPIE.3350..526L Altcode:
Several proposed spacecraft missions require positional knowledge of
their optical elements to very high precision. This knowledge can
be provided by a metrology system based on a laser interferometer
incorporating the spacecraft optics. We present results from
fabrication and testing of a lab-based frequency-modulated (FM)
Michelson interferometer intended to maintain length stability to a
few picometers. The instrument can be used to make precise relative
distance measurements or it can be used to characterize orientation and
polarization effects of system components commonly used in metrology
gauges. External frequency modulation of a frequency-stabilized laser
source and phase-sensitive detection are used to detect changes in the
arm length difference of the interferometer. Arm length adjustments
are made via a closed loop feedback system. A second system having a
shared beampath with the primary system monitors the performance of
the primary system. Preliminary data, operating in an ambient lab
environment, demonstrate control to roughly 20 picometers rms for
measurement times around 100 seconds.
---------------------------------------------------------
Title: Subnanometer laser metrology for spacecraft interferometry
Authors: Leitch, James W.; Kopp, Greg A.; Noecker, Charley
1998SPIE.3479...62L Altcode:
Several proposed space-based interferometry missions require positional
knowledge of their optical elements to very high precision. To achieve
the desired stellar position measurement precision, the internal
optical path difference of the stellar interferometer must be measured
to within 10 picometers. This knowledge can be provided by a metrology
system based on a laser interferometer incorporating the spacecraft
optics. We present results from fabrication and testing of a lab-based
frequency-modulated (FM) Michelson interferometer intended to maintain
length stability to a few picometers. The instrument can be used to make
precise relative distance measurements or it can be used to characterize
orientation and polarization effects of system components commonly used
in metrology gauges. External frequency modulation of a frequency-
stabilized laser source and phase-sensitive detection are used to
detect changes in the arm length difference of the interferometer. Arm
length adjustments are made via a closed loop feedback system. A second
system having a shared beampath with the primary system monitors the
performance of the primary system. Preliminary data, operating in an
ambient lab environment, demonstrate control to roughly 6 picometers
rms for measurement times around 10 seconds.
---------------------------------------------------------
Title: Tunable liquid-crystal filter for solar imaging at the He i
1083-nm line
Authors: Kopp, G. A.; Derks, M. J.; Elmore, D. F.; Hassler, D. M.;
Woods, J. C.; Streete, J. L.; Blankner, J. G.
1997ApOpt..36..291K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Submillimeter Radiometry of Sunspots
Authors: Lindsey, C.; Kopp, G.
1995ApJ...453..517L Altcode:
We use observations of sunspots by the 15 m James Clerk Maxwell
Telescope (JCMT) for radiometry of sunspot umbrae and penumbrae The
observations reported here, taking account of the effects of the far
wings of the JCMT's beam, show that sunspot umbrae and penumbrae vary
considerably in brightness between one another. The sunspot umbra is
typically considerably dimmer than the quiet Sun but surrounded by a
penumbra that may be fully as bright as surrounding plage. Moreover,
the vertical brightness temperature gradients of sunspot umbrae and
penumbrae appear to be uniformly positive, roughly equivalent to
that of the quiet Sun. This gradient substantiates the operation of
nonradiative heating in the low chromospheres of the strongest magnetic
regions visible on the Sun's surface, i.e., sunspot umbrae.
---------------------------------------------------------
Title: The Sun in Submillimeter and Near-Millimeter Radiation
Authors: Lindsey, C.; Kopp, G.; Clark, T. A.; Watt, G.
1995ApJ...453..511L Altcode:
We examine the best solar submillimeter observations made on the James
Clerk Maxwell Telescope in 1991 and 1992. In these observations, the
solar disk was observed concurrently in pairs of wavelengths chosen
from 350, 850, and 1200 μm. Images at all of these wavelengths show
clear limb brightening of the quiet Sun. The observations clearly
resolve the chromospheric supergranular network in active and quiet
regions. The quiet Sun is characterized by large-scale variations in
brightness, particularly the occasion of anomalously dark regions that
tend to surround active regions. Sunspots are clearly resolved, with
large dark umbrae clearly distinguished from sometimes particularly
bright penumbrae.
---------------------------------------------------------
Title: Removing Instrumental Polarization from Infrared Solar
Polarimetric Observations
Authors: Kuhn, J. R.; Balasubramaniam, K. S.; Kopp, G.; Penn, M. J.;
Dombard, A. J.; Lin, H.
1994SoPh..153..143K Altcode:
Full Stokes polarimetry is obtained using the National Solar
Observatory Vacuum Tower Telescope at Sacramento Peak while observing
the magnetically sensitive infrared FeI line at wavelength of 1.56μ. A
technique is described which makes use of the high magnetic resolution
in this spectral range to remove instrumental polarization from observed
StokesQ, U, andV line profiles.
---------------------------------------------------------
Title: A Magnetic Field Strength vs. Temperature Relation in Sunspots
Authors: Kopp, G.; Rabin, D.
1994IAUS..154..477K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of seeing at 0.5 and 12.4 μm
Authors: Livingston, W.; Kopp, G.; Gezari, D.; Varosi, F.
1994IAUS..158..299L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Imaging Solar Bolometric and Spectral Intensity Using Thermal
Detector Arrays
Authors: Deming, D.; Glenar, D.; Kostiuk, T.; Bly, V.; Forrest, K.;
Nadler, D.; Hudson, H.; Lindsey, C.; Kopp, G.; Avrett, E.; Terrill,
C. W.
1993BAAS...25R1221D Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Sunspot and Active Region Chromospheres from Submillimeter
JCMT Observations
Authors: Kopp, G.; Lindsey, C.
1993BAAS...25.1181K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: A Magnetograph Comparison Workshop
Authors: Jones, H.; Bogart, R.; Canfield, R.; Chapman, G.; Henney,
C.; Kopp, G.; Lites, B.; Mickey, D.; Montgomery, R.; Pillet, V.;
Rabin, D.; Ulrich, R.; Walton, S.
1993BAAS...25.1216J Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Intercomparison of Seven Magnetographs
Authors: Walton, S. R.; Bogart, R. S.; Chapman, G. A.; Henney, C.;
Jones, H.; Kopp, G.; Lites, B.; Mickey, D.; Montgomery, R.; Pillet,
V.; Rabin, D.
1993BAAS...25.1205W Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Helioseismic Prospects in the Mid Infrared
Authors: Kopp, G.
1993ASPC...42..473K Altcode: 1993gong.conf..473K
No abstract at ADS
---------------------------------------------------------
Title: Thermal Images of Sunspots and the Quite Sun at 4.8, 12.4,
and 18 microns
Authors: Gezari, D.; Kopp, G.; Livingston, W.
1993AAS...181.8103G Altcode: 1993BAAS...25..733G
No abstract at ADS
---------------------------------------------------------
Title: Submillimeter Solar Images from the JCMT
Authors: Kopp, G.; Lindsey, C.
1992AAS...181.9406K Altcode: 1992BAAS...24.1270K
We present nearly full-disk, diffraction-limited solar images made at
350 and 850 microns and at 1.3 mm from the 15 m James Clerk Maxwell
Telescope on Mauna Kea. These wavelengths sample the thermal structure
of the solar chromosphere at altitudes from 500 to about 1500 km,
providing a height-dependent diagnostic of the atmosphere. Filament
channels and neutral lines are apparent in the submillimeter images,
although filaments themselves are not clearly visible. The submillimeter
images show plage approximately 20% brighter than the surrounding
quiet Sun, while sunspot intensities are comparable to the quiet
Sun. “Circumfacules,” dark areas surrounding active regions,
are observed in the submillimeter images and are similar to those
seen in Ca 8542; comparison with Ca H and K may give estimates of the
temperature and filling factor of the hot gas present in these probably
bifurcated regions.
---------------------------------------------------------
Title: NIM --- A Near Infrared Magnetograph
Authors: Rabin, D.; Jaksha, D.; Kopp, G.; Mahaffey, C.
1992AAS...181.8101R Altcode: 1992BAAS...24.1251R
\newcommand{\micron}{microns} \newcommand{\kayser}{cm(-1)
} \newcommand{\NIM}{NIM} We describe a new instrument for mapping
magnetic field strength in the active solar photosphere. \NIM\ is a
Stokes spectropolarimeter that exploits the high Zeeman sensitivity of
the line Fe I 6388.64 \kayser\ (15648.5 Angstroms, e\:(7D_1) -- 3d(6) 4s
5p\:(7D^) o_1, Lande g = 3.00, chi_e = 5.36 eV) to measure vec {B}. For
|B| ga 850 G, the magnitude of the field is derived, without adjustable
parameters, from the complete splitting of the Zeeman components. The
relative strengths of the Stokes components indicate the direction of
the field. The absolute strength of the polarized signal depends on
the areal filling factor, inclination, continuum contrast, and line
strength of the magnetic flux tubes within the angular resolution
element. \NIM\ comprises the following subsystems: precision image
scanner liquid crystal polarization modulators and control electronics
slit spectrograph transfer and minification optics 128 times 128 InSb
infrared array camera computer for data acquisition and user interface
\NIM\ builds up a two-dimensional array of polarized spectra by scanning
the solar image across the spectrograph slit. The spatial and spectral
sampling frequencies are 1.0 arcsec or 0.5 arcsec per pixel (depending
on which telescope is used) and 0.025 \kayser\ per pixel. At each slit
position, 8 polarization pairs for each Stokes parameter (e.g., +/- V)
are acquired at 7 Hz, averaged, and recorded in FITS format. A 128 times
128 arcsec(2) map is acquired in about 20 minutes. \NIM\ is available
to NSO visiting observers at the McMath-Pierce Telescope on Kitt Peak.
---------------------------------------------------------
Title: Thermal Maps of Sunspots and the Quiet Sun
Authors: Livingston, W.; Kopp, G.; Gezari, D.
1992AAS...181.8103L Altcode: 1992BAAS...24.1252L
We present images of sunspots, surrounding plage, quiet Sun, and
the solar limb made at 4.8, 12.4, and 18 microns. These are basically
thermal maps, the infrared intensity being nearly linearly proportional
to temperature at these wavelengths. We believe these to be the most
detailed thermal images to date of the solar photosphere. Thermal
structure within sunspot penumbrae and the surrounding plage is evident
in several images, although umbrae appear homogeneous, at least down
to the approximately 2” diffraction limit of the telescope at 12
microns. We find the temperature of penumbrae to be roughly 5% less
than that of the quiet Sun, and umbrae to be about 25% less. Images
of the quiet Sun show spatial thermal fluctuations of about 2% in
patterns that change slowly with time. The measurements were made
with the NSO's windowless, filled-aperture 1.6 m McMath-Pierce Solar
Telescope, which fed the infrared image to a cryogenically-cooled
58x62 Si:Ge camera system built by D. Gezari.
---------------------------------------------------------
Title: A Relation Between Magnetic Field Strength and Temperature
in Sunspots
Authors: Kopp, Greg; Rabin, Douglas
1992SoPh..141..253K Altcode:
We present Stokes I Zeeman splitting measurements of sunspots using the
highly sensitive (g = 3) Fe I line at λ = 1.5649 μm. The splittings
are compared with simultaneous intensity measurements in the adjacent
continuum. The relation between magnetic field strength and temperature
has a characteristic, nonlinear shape in all the spots studied. In the
umbra, there is an approximately linear relation between B<SUP>2</SUP>
and T<SUB>b</SUB>, consistent with magnetohydrostatic equilibrium in
a nearly vertical field. A distinct flattening of the B<SUP>2</SUP> vs
T<SUB>b</SUB>relationship in the inner penumbra may be due to changes
in the lateral pressure balance as the magnetic field becomes more
horizontal; spatially unresolved intensity inhomogeneities may also
influence the observed relation.
---------------------------------------------------------
Title: Infrared Determinations of Magnetic Profiles in Sunspots
Authors: Kopp, G.; Kuhn, J.; Lin, H.; Rabin, D.
1992AAS...180.1202K Altcode: 1992BAAS...24R.747K
We present measurements of a sunspot using unpolarized observations of
the magnetically-sensitive (Lande g=3) Fe I line at lambda =1.5649
microns (6388.6 cm(-1) ). We compare the magnetic field profile
from this fairly symmetric spot with model profiles. Splittings
in this infrared line are nearly a factor of 3 greater than in a
comparable visible line, since Zeeman splitting as a fraction of
linewidth increases linearly with wavelength. The infrared is also
less affected by stray light than the visible, because the intensity
contrast is reduced, decreasing the effects of stray light, and because
instrumental scatter is lower in the infrared. The combination of the
magnetic and stray light advantages of the infrared and the recent
availability of “large” infrared arrays has made possible more
sensitive determinations of the magnetic field profile throughout
sunspots. From observations of several sunspots, we find that the
magnetic field strength, determined in the strong field regime, is not
a smooth function of radius from spot center, and that single radial
parameter models do not accurately describe the observed spots.
---------------------------------------------------------
Title: Chromospheric Dynamics Based on Infrared Solar Brightness
Variations
Authors: Kopp, G.; Lindsey, C.; Roellig, T. L.; Werner, M. W.; Becklin,
E. E.; Orrall, F. Q.; Jefferies, J. T.
1992ApJ...388..203K Altcode:
The NASA Kuiper Airborne Observatory was used to observe far-infrared
continuum brightness fluctuations in the lower chromosphere due to
solar 5 minute oscillations on the quiet sun. Brightness measurements
made at 50, 100, 200, and 400 microns show a strong correlation with
visible-line Doppler measurements from photospheric and chromospheric
altitudes. The motion of the chromosphere is nearly in phase over a
large range of heights, while the infrared brightness lags the Doppler
velocity by phases varying from significantly less than 90 deg at low
altitudes to nearly 90 deg at higher altitudes. It is proposed that
this is the result of a nonadiabatic response of the chromospheric
gas to compression and may indicate an important mechanism for wave
dissipation. Thermal relaxation times ranging from about 40 s at
340 km above the tau(5000) = 1 photosphere to about 300 s at 600 km
are proposed.
---------------------------------------------------------
Title: Submillimeter Solar Limb Profiles Determined from Observations
of the Total Solar Eclipse of 1988 March 18
Authors: Roellig, T. L.; Becklin, E. E.; Jefferies, J. T.; Kopp,
G. A.; Lindsey, C. A.; Orrall, F. Q.; Werner, M. W.
1991ApJ...381..288R Altcode:
Observations were made of the extreme solar limb in six far-infrared
wavelength bands ranging from 30 to 670 micron using the Kuiper
Airborne Observatory during the total eclipse of the sun on 1988 March
18. By observations of the occultation of the solar limb by the moon,
it was possible to obtain a spatial resolution of 0.5 arcsec normal
to the limb. The solar limb was found to be extended with respect
to the visible limb at all of these wavelengths, with the extension
increasing with wavelength. Limb brightening was observed to increase
slightly with increasing wavelength, and no sign of a sharp emission
spike at the extreme limb was found at any of these wavelengths. The
observations can be well fitted by a chromospheric model incorporating
cool dense spicules in the lower chromosphere.
---------------------------------------------------------
Title: Zeeman Splitting and Continuum Measurements of Sunspots at
1.56 μm
Authors: Kopp, G.; Rabin, D.; Lindsey, C.
1991BAAS...23.1055K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Modelling of Chromospheric Dynamics Based on Infrared Solar
Brightness Variations
Authors: Kopp, G.
1990BAAS...22..896K Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Far-Infrared Intensity Variations Caused by 5 Minute
Oscillations
Authors: Lindsey, C.; Kopp, G.; Becklin, E. E.; Roellig, T.; Werner,
M. W.; Jefferies, J. T.; Orrall, F. Q.; Braun, D.; Mickey, D. L.
1990ApJ...350..475L Altcode:
Observations of solar IR intensity variations at 50, 100, and
200 microns were made simultaneously and cospatially with Doppler
measurements in the sodium D1 line at 5896 A. Brightness temperature
variations of several K in amplitude are highly correlated with five
minute Doppler oscillations. The brightness variations are attributed
to work done on the chromospheric medium by compression, driven by the
five minute oscillations. The Doppler oscillations lead the brightness
variations by about 47 deg in phase at 50 and 100 microns and by about
72 deg in phase at 200 microns.
---------------------------------------------------------
Title: Chromospheric Dynamics Based on Infrared Solar Brightness
Variations
Authors: Kopp, Greg
1990PhDT........10K Altcode:
Infrared techniques were used to observe continuum emission from
the solar chromosphere near temperature minimum in order to model the
thermal response of the atmosphere to compressions due to 5-minute solar
oscillations. Using one airborne and two ground-based observatories,
simultaneous infrared intensity (temperature) and visible Doppler
velocity measurements were acquired at several heights in the
chromosphere, thus allowing comparisons between the motions of
the atmospheric gas and the thermal fluctuations. While 5-minute
oscillations in the lower chromosphere are frequently thought to
be evanescent, so that the compression of the gas is in phase at
all heights, the temperature changes due to these oscillations
are found to vary in phase with altitude, implying the gas behaves
non-adiabatically in this region. The phases between the velocities of
the gas and the temperature fluctuations were determined at several
heights near temperature minimum. The chromosphere was then modelled
as a planar gravitationally-stratified gas with thermal relaxation
toward an equilibrium, isothermal temperature permitted in the equation
describing temperature change with compression. The rates of thermal
relaxation at different altitudes were estimated from the observed
phases between the infrared and visible data. The relaxation times
were found to vary from 30 seconds at an altitude of 350 km above the
photosphere to roughly 200 seconds at 600 km altitude. The effects of
compression on the opacity of the gas were also studied, in order to
predict the consequences of a non-isothermal atmosphere on the continuum
observations. An estimate of the energy lost from solar oscillations
due to thermal relaxation is calculated for the altitudes observed,
and it appears that solar oscillations may be partially responsible
for heating the lower chromosphere by thermal relaxation.
---------------------------------------------------------
Title: Profiles of the Extreme Solar Limb at Far Infrared and
Submillimeter Wavelengths
Authors: Roellig, T. L.; Werner, M. W.; Kopp, G.; Becklin, E. E.;
Lindsey, C.; Orrall, F. Q.; Jefferies, J. T.
1989BAAS...21..765R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Submillimeter Observations of the Extreme Solar Limb by
Occultation in the Total Solar Eclipse of 18 March 1988
Authors: Roellig, T. R.; Werner, M. W.; Kopp, G.; Becklin, E. E.;
Lindsey, C.; Orrall, F. Q.; Jefferies, J. T.
1988BAAS...20..689R Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Simultaneous Observations of Far-Infrared Solar Continuum
Brightness Variations and Five-Minute Oscillations
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Kopp, G.; Werner,
M. W.; Roellig, T. R.
1988BAAS...20..690L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Modeling the Solar Chromosphere by Airborne Solar Eclipse
Observations
Authors: Orrall, F. Q.; Becklin, E. E.; Lindsey, C.; Roellig, T. R.;
Werner, M. W.; Kopp, G.; Jefferies, J. T.
1987BAAS...19.1014O Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of Far-Infrared Solar Continuum Variations Due
to Compression Waves
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.;
Roellig, T. R.; Kopp, G.; Jefferies, J. T.
1987BAAS...19S1014L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of Far-Infrared Solar Continuum Variations Due
to Compression Waves
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.;
Roellig, T. R.; Kopp, G.
1987BAAS...19R.933L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of far-infrared solar continuum variations due
to compression waves.
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.;
Roellig, T. R.; Kopp, G.
1987BAAS...19..933L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of far-infrared solar continuum variations due
to compression waves.
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.;
Roellig, T. R.; Kopp, G.
1987BAAS...19..741L Altcode:
No abstract at ADS
---------------------------------------------------------
Title: Observations of Far-Infrared Solar Continuum Variations Due
to Compression Waves
Authors: Lindsey, C.; Becklin, E. E.; Orrall, F. Q.; Werner, M. W.;
Roellig, T. R.; Kopp, G.
1987BAAS...19R.741L Altcode:
No abstract at ADS
