Author name code: mount ADS astronomy entries on 2022-09-14 author:"Mount, George" ------------------------------------------------------------------------ Title: Ozone monitoring instrument flight-model on-ground and inflight calibration Authors: Dobber, Marcel; Dirksen, Ruud; Levelt, Pieternel F.; van den Oord, Gijsbertus; Jaross, Glen; Kowalewski, Matt; Mount, George H.; Heath, Donald; Hilsenrath, Ernest; Cebula, Richard Bibcode: 2017SPIE10568E..0CD Altcode: The Ozone Monitoring Instrument (OMI) is an ultravioletvisible imaging spectrograph that uses two-dimensional CCD detectors to register both the spectrum and the swath perpendicular to the flight direction. This allows having a 114 degrees wide swath combined with an unprecedented small ground pixel (nominally 13 x 24 km2), which in turn enables global daily ground coverage with high spatial resolution. The OMI instrument is part of NASA's EOSAURA satellite, which will be launched in the second half of 2004. The on-ground calibration of the instrument was performed in 2002. This paper presents and discusses results for a number of selected topics from the on-ground calibration: the radiometric calibration, the spectral calibration and spectral slit function calibration. A new method for accurately calibrating spectral slit functions, based on an echelle grating optical stimulus, is discussed. The in-flight calibration and trend monitoring approach and facilities are discussed. Title: Status of the Geostationary Spectrograph (GeoSpec) for Earth and Atmospheric Science Applications Authors: Janz, S. J.; Hilsenrath, E.; Mount, G.; Brune, W.; Heath, D. Bibcode: 2004AGUFMSF43A0772J Altcode: GeoSpec will support future satellite mission concepts in the Atmospheric Sciences and in Land and Ocean Sciences by providing time-resolved measurements of both chemically linked atmospheric trace gas concentrations of important molecules such as O3, NO2, CH2O and SO2 and at the same time coastal and ocean pollution events, tidal effects, and the origin and evolution of aerosol plumes. The instrument design concept in development is a dual spectrograph covering the UV/VIS wavelength region of 310-500 nm and the VIS/NIR wavelength region of 480-940 nm coupled to all reflective telescope and high sensitivity PIN/CMOS area detectors. The goal of the project is to demonstrate a system capable of making moderate spatial resolution (1 km at nadir) hyperspectral measurements (1.0 to 1.5 nm resolution) from a geostationary orbit. This will enable studies of time-varying pollution and coastal change processes with a temporal resolution of 15 minutes on a regional scale to 1 hour on a continental scale. Other spatial and temporal resolutions can be supported by varying the focal length of the input telescope and scanning strategies. Scientific rationale and instrument design and status will be presented. Title: Ozone Monitoring Instrument flight-model on-ground and in-flight calibration Authors: Dobber, Marcel; Dirksen, Ruud; Levelt, Pieternel F.; van den Oord, Gijsbertus; Jaross, Glen; Kowalewski, Matt; Mount, George H.; Heath, Donald; Hilsenrath, Ernest; Cebula, Richard Bibcode: 2004ESASP.554...89D Altcode: 2004icso.conf...89D The Ozone Monitoring Instrument (OMI) is an ultraviolet-visible imaging spectrograph that uses two-dimensional CCD detectors to register both the spectrum and the swath perpendicular to the flight direction. This allows having a 114 degrees wide swath combined with an unprecedented small ground pixel (nominally 13×24 km2), which in turn enables global daily ground coverage with high spatial resolution. The OMI instrument is part of NASA's EOS-AURA satellite, which will be launched in the second half of 2004. The on-ground calibration of the instrument was performed in 2002. This paper presents and discusses results for a number of selected topics from the on-ground calibration: the radiometric calibration, the spectral calibration and spectral slit function calibration. A new method for accurately calibrating spectral slit functions, based on an echelle grating optical stimulus, is discussed. The in-flight calibration and trend monitoring approach and facilities are discussed. Title: Status of the geostationary spectrograph (GeoSpec) for earth and atmospheric science applications Authors: Janz, S.; Hilsenrath, E.; Mount, G.; Brune, W.; Heath, D. Bibcode: 2004cosp...35.4385J Altcode: 2004cosp.meet.4385J GeoSpec will support future satellite mission concepts in the Atmospheric Sciences and in Land and Ocean Sciences by providing time-resolved measurements of both chemically linked atmospheric trace gas concentrations of important molecules such as O_3, NO_2, CH_2O and SO_2 and at the same time coastal and ocean pollution events, tidal effects, and the origin and evolution of aerosol plumes. The instrument design concept in development is a dual spectrograph covering the UV/VIS wavelength region of 310-500 nm and the VIS/NIR wavelength region of 480-900 nm coupled to all reflective telescope and high sensitivity PIN/CMOS area detector. The goal of the project is to demonstrate a system capable of making moderate spatial resolution (750 meters at nadir) hyperspectral measurements (0.6 to 1.2 nm resolution) from a geostationary orbit. This would enable studies of time-varying pollution and coastal change processes with a temporal resolution of 5 minutes on a regional scale to 1 hour on a continental scale. Other spatial resolutions can be supported by varying the focal length of the input telescope. Scientific rationale and instrument design and status will be presented. Title: Middle Atmosphere High Resolution Spectrograph Investigation Authors: Conway, Robert R.; Stevens, Michael H.; Brown, Charles M.; Cardon, Joel G.; Zasadil, Scott E.; Mount, George H. Bibcode: 1999JGR...10416327C Altcode: The Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) was developed specifically to measure the vertical density profiles of hydroxyl (OH) and nitric oxide (NO) in the middle atmosphere from space. MAHRSI was launched on its first flight in November 1994 on the CRISTA-SPAS satellite that was deployed and retrieved by the space shuttle. The instrument measured the radiance profiles of ultraviolet solar resonance fluorescence on the Earth's limb with a spectral resolving power of 15,600 at a wavelength of 308 nm and 7200 at 215 nm. The instantaneous height of the field of view projected to the tangent point was about 300 m. OH limb radiance measurements were made between altitudes of 90 and 30 km, and each limb scan extended over a horizontal distance of 1200 km. For NO a limb scan extended between altitudes of 140 and 76 km and over a horizontal distance 700 km. Observations were made from 52°S latitude to 62°N latitude. The OH measurements have been inverted to provide the first global maps of the vertical distribution of OH between 90 and 50 km. The data show a detailed history of the morning formation of a strongly peaked layer of OH at an altitude of 68 km. This layer was produced by solar photodissociation of a thin layer of water vapor peaked at 65 km extending between 30°S and 35°N observed contemporaneously by the Halogen Occultation Experiment (HALOE) on the Upper Atmosphere Research Satellite. MAHRSI was successfully flown for a second time in August 1997 under conditions that extended the geographical coverage to 72°N latitude and local solar time coverage through the afternoon hours. This paper provides a detailed description of the experiment and instrumentation, of the algorithms used to reduce the spectral data and perform the inversions, and presents examples of key results from the 1994 flight. Title: Solar Spectral Irradiance Measuremetns: Visible to Near-Infrared Regions Authors: Rottman, G.; Mount, G.; Lawrence, G.; Woods, T.; Harder, J.; Tournois, S. Bibcode: 1998Metro..35..707R Altcode: No abstract at ADS Title: Satellite measurements of hydroxyl in the mesosphere Authors: Conway, Robert R.; Stevens, Michael H.; Cardon, Joel G.; Zasadil, Scott E.; Brown, Charles M.; Morrill, Jeff S.; Mount, George H. Bibcode: 1996GeoRL..23.2093C Altcode: The global distribution of hydroxyl (OH) in the middle atmosphere was recently measured by the Middle Atmosphere High Resolution Spectrograph Investigation (MAHRSI) on a satellite deployed and retrieved by the space shuttle. During 75 orbits, MAHRSI acquired 1800 daytime limb scans of the OH ultraviolet solar resonance fluorescence intensity. Each limb scan extends over the altitude region from 30 to 90 km and across 10° of latitude between 53°S and 63°N. OH number densities were retrieved using a Twomey regularization scheme constrained by the smoothness of the retrieved profile. Results provide a detailed description of the diurnal variation of mesospheric OH. Midmorning OH densities had a well defined peak of about 6 ×106 cm³ near 70 km, a broad minimum centered near 64 km, and rose to about 1 × 107 cm³ at 50 km. This profile is in substantial disagreement with photochemical model predictions [Summers et al., this issue]. The observations are compared with the two previous measurements. Title: Visible and near-ultraviolet spectroscopy at McMurdo Station, Antarctica. VIII - Observations of nighttime NO2 and NO3 from April to October 1991 Authors: Solomon, S.; Smith, J. P.; Sanders, R. W.; Perliski, L.; Miller, H. L.; Mount, G. H.; Keys, J. G.; Schmeltekopf, A. L. Bibcode: 1993JGR....98..993S Altcode: Lunar absorption spectra have been used to determine the vertical column abundances of NO2 and NO3 above McMurdo Station, Antarctica, during the fall, winter, and spring seasons in 1991. The observed nighttime NO2 and NO3 amounts during the fall and spring were broadly consistent with model predictions and with daytime measurements. During winter, local photochemistry would imply a long polar night, with associated gradual removal of NO2 and buildup of NO3 and N2O5. The winter observations of both species differ from such simple predictions by factors greater than 10, with the measured NO2 being far larger than predicted, while the measured NO3 is much smaller than predicted. The concurrent measurements of both NO2 and NO3 strongly constrain possible solutions for these discrepancies and suggest that air parcel excursions to sunlit, lower latitudes likely take place quite regularly throughout the winter (approximately every 3-7 days). Title: An Intercomparison of Tropospheric OH Measurements at Fritz Peak Observatory, Colorado Authors: Mount, George H.; Eisele, Fred L. Bibcode: 1992Sci...256.1187M Altcode: The hydroxyl radical (OH) controls the lifetimes and therefore the concentrations of many important chemical species in Earth's lower atmosphere including several greenhouse and ozone-depleting species. Two completely different measurement techniques were used in an informal intercomparison to determine tropospheric OH concentrations at Fritz Peak Observatory, Colorado, from 15 July to 24 August 1991. One technique determined OH concentrations by chemical analysis; the other used spectroscopic absorption on a long path. The intercomparison showed that ambient OH concentrations can now be measured with sufficient sensitivity to provide a test for photochemical models, with the derived OH concentrations agreeing well under both polluted and clean atmospheric conditions. Concentrations of OH on all days were significantly lower than model predictions, perhaps indicating the presence of an unknown scavenger. The change in OH concentration from early morning to noon on a clear day was found to be only a factor of 2. Title: Interference effects in reticon photodiode array detectors Authors: Mount, George H.; Sanders, Ryan W.; Brault, James W. Bibcode: 1992ApOpt..31..851M Altcode: A detector system incorporating the Reticon RL1024S photodiode array has been constructed as part of a double spectrograph to be used to study the earth's atmosphere from ground-based and aircraft-based platforms. To determine accurately the abundances of atmospheric trace gases, this new system must be able to measure spectral absorptions as small as 0.02 percent. The detector exhibits superior signal-to-noise characteristics at the light levels characteristic of scattered skylights, but interference in the passivating layer causes problems in achieving the required precision. The mechanism of the problems and the solution implemented are described in detail. Title: New spectroscopic instrumentation for measurement of stratospheric trace species by remote sensing of scattered skylight Authors: Mount, George H.; Jakoubek, R. O.; Sanders, R. W.; Harder, J. W.; Solomon, S.; Winkler, R.; Thompson, T.; Harrop, W. Bibcode: 1991SPIE.1491..188M Altcode: Instrumentation under construction and testing at the NOAA Aeronomy Laboratory for conducting measurements of the zenith sky and the moon in order to measure molecular abundances of trace gases in the stratosphere at extremely low levels of absorption (less than 0.05 percent) is discussed. The instrumentation consists of a telescope (for lunar observation at night or direct sun during the day), a light feed, a spectrograph, an array detector, and a data analysis system. The telescope design is a dual off-axis parabolic feed with polarizers, depolarizers, image rotators, and other optical modifiers that can be inserted at the feed focus to test their effect on the residual spectrum. The spectrograph is a cast aluminum 3/8-m f/6 double crossed Czerny-Turner system. Title: Long path differential absorption measurements of tropospheric molecules Authors: Harder, Jerald; Mount, George Bibcode: 1991SPIE.1491...33H Altcode: The measurement of the important atmospheric molecules O3, NO2, CH2O, H2O, NO3, and HONO can be measured using long path differential absorption spectroscopy. The experiment is located at the Fritz Peak Observatory, 17 km west of Boulder, Colorado. This site permits both the measurement of clean continental air during times of westerly air flow, as well as polluted urban air during easterly up-slope episodes. The spectrograph used in this study is a low resolution double crossed Czerny-Turner, with a well matched receiving telescope. This spectrograph uses a 1 x 1024 element Reticon diode array detector to measure the molecular absorption spectra of these molecules in 40 nm bands in the near ultraviolet-visible region. The total optical path for this experiment is 20.6 km, and the path is folded by a 121 element retroreflector array thereby allowing the light source and spectrograph to be in the same location. Deduction of atmospheric concentrations these molecules over this path is accomplished by using a least squares procedure that employs the method of singular-value decomposition. Title: Atmospheric NO3. II - Observations in polar regions Authors: Solomon, S.; Sanders, R. W.; Mount, G. H.; Carroll, M. A.; Jakoubek, R. O. Bibcode: 1989JGR....9416423S Altcode: Stratospheric NO3 is expected to depend strongly upon two major factors: solar illumination and temperature. This paper presents observations in the polar regions that confirm the influence of both of these on the NO3 column abundance. Measurements of the absorption of incoming lunar radiation near 662 nm as the sun rises exhibit large changes that apparently reflect the rapid photolysis of NO3. The increase in upper stratospheric temperature that occurs in early spring in polar regions should also affect the seasonal changes in stratospheric NO3 abundances. Observations of stratospheric NO3 at 76.5 deg N in early February are contrasted with those obtained at 77.8 deg S in late August and September. Large seasonal differences in stratospheric temperatures between these two locations and times are shown to be in excellent agreement with the observed NO3 column amounts, providing further support for current understanding of the factors controlling the stratospheric NO3 abundance and its variability. These findings provide further evidence against a stratospheric 'scavenger' for NO3, even in polar latitudes, where the scavenging effect was believed to be most pronounced. Title: Remote sensing observations of nighttime OClO column during the Airborne Antarctic Ozone Experiment, September 8, 1987 Authors: Wahner, A.; Jakoubek, R. O.; Mount, G. H.; Ravishankara, A. R.; Schmeltekopf, A. L. Bibcode: 1989JGR....9411405W Altcode: The daytime and nighttime slant column abundances of OClO were measured by near-UV absorption spectroscopy between 64 and 76 deg S latitude and 62 and 84 deg W longitude during the DC-8 flight on days 251 and 252 (UT) 1987 as a part of the Airborne Antarctic Ozone Experiment (AAOE). Daytime and nighttime measurements used the scattered sunlight and the moon as the light sources, respectively. The measured OClO column abundance during the nighttime was found to be 10 times larger than that measured during the day. Title: Observations of the Nighttime Abundance of OClO in the Winter Stratosphere above Thule, Greenland Authors: Solomon, S.; Mount, G. H.; Sanders, R. W.; Jakoubek, R. O.; Schmeltekopf, A. L. Bibcode: 1988Sci...242..550S Altcode: Observations at Thule, Greenland, that made use of direct light from the moon on 2, 3, 4, 5, and 7 February 1988 revealed nighttime chlorine dioxide (OClO) abundances that were less than those obtained in Antarctica by about a factor of 5, but that exceeded model predictions based on homogeneous (gas-phase) photochemistry by about a factor of 10. The observed time scale for the formation of OClO after sunset strongly supports the current understanding of the diurnal chemistry of OClO. These data suggest that heterogeneous (surface) reactions due to polar stratospheric clouds can occur in the Arctic, providing a mechanism for possible Arctic ozone depletion. Title: Observations of Stratospheric NO2 and O3 at Thule, Greenland Authors: Mount, G. H.; Solomon, S.; Sanders, R. W.; Jakoubek, R. O.; Schmeltekopf, A. L. Bibcode: 1988Sci...242..555M Altcode: Scattered sunlight and direct light from the moon was used in two wavelength ranges to measure the total column abundances of stratospheric ozone (O3) and nitrogen dioxide (NO2) at Thule, Greenland (76.5 degrees N), during the period from 29 January to 16 February 1988. The observed O3 column varied between about 325 and 400 Dobson units, and the lower values were observed when the center of the Arctic polar vortex was closest to Thule. This gradient probably indicates that O3 levels decrease due to dynamical processes near the center of the Arctic vortex and should be considered in attempts to derive trends in O3 levels. The observed NO2 levels were also lowest in the center of the Arctic vortex and were sometimes as low as 5 × 1014 molecules per square centimeter, which is even less than comparable values measured during Antarctic spring, suggesting that significant heterogeneous photochemistry takes place during the Arctic winter as it does in the Antarctic. Title: Middle atmosphere high resolution spectrograph Authors: Conway, R. R.; Prinz, D. K.; Mount, G. H. Bibcode: 1988SPIE..932...50C Altcode: The U.S. Naval Research laboratory's middle atmosphere high-resolution spectrograph (MAHRS), part of the Air Force Test Program's Spartan-282 shuttle payload, is described. The goals of the MAHRS experiment are to determine the abundances of nitric oxide and hydroxyl radical in the altitude range of 50-150 km and to measure the diurnal global variation of these species. The MAHRS instrument was designed to produce a flat image at the surface of a 15-mm high x 25-mm wide microchannel-plate-intensified two-dimensional array detector with a cesium telluride photocathode and a 0.025 mm spatial resolution. Title: Visible spectroscopy at McMurdo station, Antarctica. III - Observations of NO3 Authors: Sanders, R. W.; Solomon, S.; Mount, G. H.; Schmeltekopf, A. L.; Bates, M. W. Bibcode: 1987JGR....92.8339S Altcode: The total column abundance of NO3 was measured in Antarctica during the nights of Sept. 17-19, 1986, by visible absorption, using the moon as the light source. The variation of the observed abundance with lunar zenith angle suggests that the bulk of the layer is located in the stratosphere. In agreement with theoretical model calculations, the total column was about 2.0 x 10 to the 13th molecule/sq cm and increased systematically with time during the night. Title: Solar absolute spectral irradiance 118-300 nm: July 25, 1983 Authors: Mount, G. H.; Rottman, G. J. Bibcode: 1985JGR....9013031M Altcode: The full-disk solar absolute spectral irradiance in the spectral range 118-300 nm was obtained from a rocket observation above White Sands Missile Range, New Mexico, on July 25, 1983, halfway in time between solar maximum and solar minimum. Comparison with measurements made in May 1982 shows no changes within the absolute errors of the experiment. Comparison with measurements made during solar maximum in 1979 and 1980 indicates a large decrease in the absolute solar irradiance at wavelengths below 190 nm. The absolute calibration of the instruments for this flight was accomplished at the National Bureau of Standards Synchrotron Radiation Facility. Title: Solar Mesosphere Explorer ultraviolet Spectrometer Measurements of ozone in the 1.0-0.1 mbar region Authors: Rusch, D. W.; Barth, C. A.; Thomas, R. J.; Callan, M. T.; Mount, G. H. Bibcode: 1984JGR....8911677R Altcode: The ozone density of the earth's mesosphere in the 1.0-0.1 mbar (48 to 70 km) region has been measured at sunlit latitudes for the period from December 1981 until the present by an ultraviolet spectrometer on the Solar Mesosphere Explorer satellite. Results for 1982 are reported. The ozone mixing ratios are found to be highly variable in time and place, with maxima occurring in the winter hemispheres. The results show complex time variations at all pressure levels, with annual and semiannual variations apparent at most pressures and latitudes. A relative maximum occurs in July at the equator. Title: Measurements of stratospheric NO2 from the Solar Mesosphere Explorer satellite. II - General morphology of observed NO2 and derived (N2)O5 Authors: Solomon, S.; Mount, G. H.; Zawodny, J. M. Bibcode: 1984JGR....89.7317S Altcode: Observations of NO2 densities from 28 to 40 km as measured by the Solar Mesosphere Explorer (SME) satellite are compared to model calculations for the month of January. Low densities are obtained in the tropics and in high latitude winter, with much larger values in the summer middle and high latitude regions in both the observations and the model. The reasons for areas of agreement and disagreement between the model and the observations are explored. The observed NO2 distribution is also used to infer the N2O5 distribution based on presently accepted chemistry and suggests that very large amounts of N2O5 are present in high latitude winter. Title: The Solar Absolute Spectral Irradiance at 1216 Å and 1800-3173 Å: January 12, 1983 Authors: Mount, G. H.; Rottman, G. J. Bibcode: 1983JGR....88.6807M Altcode: The full-disk solar spectral irradiance in the spectral range 1800-3173 Å and at Ly α was obtained from a rocket observation above White Sands Missile Range, New Mexico, on January 12,1983. Comparison with measurements made in May 1983 show no changes within the absolute errors of the experiment. The absolute calibration of the instruments for this flight was accomplished at the National Bureau of Standards Synchrotron Radiation Facility. Title: The solar absolute spectral irradiance 1150 - 3173 Å: May 17, 1982. Authors: Mount, G. H.; Rottman, G. J. Bibcode: 1983JGR....88.5403M Altcode: The full-disk solar spectral irradiance in the spectral range 1150-3173 A was obtained from a rocket observation above White Sands Missile Range, NM, on May 17, 1982, half way in time between solar maximum and solar minimum. Comparison with measurements made during solar maximum in 1980 indicate a large decrease in the absolute solar irradiance at wavelengths below 1900 A to approximately solar minimum values. No change above 1900 A from solar maximum to this flight was observed to within the errors of the measurements. Irradiance values lower than the Broadfoot results in the 2100-2500 A spectral range are found, but excellent agreement with Broadfoot between 2500 and 3173 A is found. The absolute calibration of the instruments for this flight was accomplished at the National Bureau of Standards Synchrotron Radiation Facility which significantly improves calibration of solar measurements made in this spectral region. Title: Ozone densities in the lower mesosphere measured by a limb scanning ultraviolet spectrometer Authors: Rusch, D. W.; Mount, G. H.; Barth, C. A.; Rottman, G. J.; Thomas, R. J.; Thomas, G. E.; Sanders, R. W.; Lawrence, G. M.; Eckman, R. S. Bibcode: 1983GeoRL..10..241R Altcode: The ozone content of the earth's atmosphere between 1 mb and 0.08 mb has been measured as a function of latitude and season by an ultraviolet spectrometer on the Solar Mesosphere Explorer spacecraft. The ozone mixing ratio is found to be highly variable in time and space during the winter of 1982 with maxima occuring in the winter hemisphere during January and February at all pressure levels. The latitude gradients near spring equinox are relatively small. A relative maximum occurs at latitudes between 15 and 30°S in January and February. Title: Ozone density distribution in the mesosphere (50-90 km) measured by the SME limb scanning near infrared spectrometer Authors: Thomas, R. J.; Barth, C. A.; Rottman, G. J.; Rusch, D. W.; Mount, G. H.; Lawrence, G. M.; Sanders, R. W.; Thomas, G. E.; Clemens, L. E. Bibcode: 1983GeoRL..10..245T Altcode: The ozone densities between 50 and 90 km are deduced from 1.27 µm airglow measured on the Solar Mesosphere Explorer satellite. The derived densities agree well with those made simultaneously from SME by the ultraviolet spectrometer. The data set extends from pole to pole at about 3 pm, for most sunlit latitudes. At low altitudes, in the mesosphere, there are larger variations in ozone density in the winter latitudes than in the summer. Above the meso-pause the day-to-day variation in ozone density is a factor of two at most latitudes and times. Title: Temperature measurements in the Earth's stratosphere using a limb scanning visible light spectrometer Authors: Rusch, D. W.; Mount, G. H.; Zawodny, J. M.; Barth, C. A.; Rottman, G. J.; Thomas, R. J.; Thomas, G. E.; Sanders, R. W.; Lawrence, G. M. Bibcode: 1983GeoRL..10..261R Altcode: The temperature of the earth's atmosphere between 40 and 50 km is inferred from measurements of Rayleigh scattered sunlight by a visible-light spectrometer on the Solar Mesosphere Explorer spacecraft. The RMS deviation of the satellite measurements from conventional rocket measurements is 5°K above 45 km and 2-3°K below 45 km. The satellite data are compared to model temperatures for March, 1982. Title: Solar Mesosphere Explorer: Scientific objectives and results Authors: Barth, C. A.; Rusch, D. W.; Thomas, R. J.; Mount, G. H.; Rottman, G. J.; Thomas, G. E.; Sanders, R. W.; Lawrence, G. M. Bibcode: 1983GeoRL..10..237B Altcode: Instruments on the Solar Mesosphere Explorer simultaneously measure ozone density, temperature, and solar ultraviolet flux. Results from six months of observations show that ozone density in the mesosphere changes from day-to-day and with the seasons and that the principal cause of these changes is the variation in atmospheric temperature. The dependence between ozone density and temperature is inverse, with a decrease in temperature producing an increase in ozone density. This dependence is observable in the seasonal patterns and also in orbit-to-orbit observations during dramatic atmosphere changes such as stratospheric warmings. Title: Mesospheric ozone depletion during the Solar Proton Event of July 13, 1982 Part I Measurement Authors: Thomas, R. J.; Barth, C. A.; Rottman, G. J.; Rusch, D. W.; Mount, G. H.; Lawrence, G. M.; Sanders, R. W.; Thomas, G. E.; Clemens, L. E. Bibcode: 1983GeoRL..10..253T Altcode: The near infrared spectrometer and the ultraviolet spectrometer on the Solar Mesosphere Explorer (SME) observed the ozone density as a function of latitude and altitude during the solar proton event of July 13, 1982. Airglow at 1.27 µm was observed at the earth's limb. The altitude profiles of the emission were inverted providing ozone densities. The ozone densities observed showed a clear decrease during the event. The maximum depletion seen was 70%. The decrease was observed in the northern high latitudes at mesospheric altitudes. The decrease was very short lived, lasting less than a day. Title: Measurements of NO2 in the Earth's stratosphere using a limb scanning visible light spectrometer Authors: Mount, G. H.; Rusch, D. W.; Zawodny, J. M.; Noxon, J. F.; Barth, C. A.; Rottman, G. J.; Thomas, R. J.; Thomas, G. E.; Sanders, R. W.; Lawrence, G. M. Bibcode: 1983GeoRL..10..265M Altcode: NO2 densities determined from the limb scanning visible light spectrometer on board the Solar Mesosphere Explorer spacecraft are reported for winter 1981/82 in the altitude region 28-40 km. The observational technique utilizes the photoabsorption by NO2 of Rayleigh scattered sunlight in the 440nm spectral region. The NO2 density varies from pole to pole and shows large variations at high northern latitudes during the winter months which are related to both the temperature and flow of air near 30 km. Title: Solar mesosphere Explorer measurements of the El Chichon volcanic cloud Authors: Barth, C. A.; Sanders, R. W.; Thomas, G. E.; Rottman, G. J.; Rusch, D. W.; Thomas, R. J.; Mount, G. H.; Lawrence, G. M.; Zawodny, J. M.; West, R. A. Bibcode: 1982BAMS...63.1314B Altcode: 1982AMSBu..63.1314B After quenching from a temperature above 900°C the structure of Kh20N73YuM alloy is supersaturated solid solution. Recrystallization temperature for the alloy is 900°C, and alloy structure in relation to melting method is characterized by a different volume recrystallized matrix which is caused by the degree of prior deformation and metal purity. Title: Solar spectral irradiance, 120 to 190nm, October 13, 1981 - January 3, 1982 Authors: Rottman, G. J.; Barth, C. A.; Thomas, R. J.; Mount, G. H.; Lawrence, G. M.; Rusch, D. W.; Sanders, R. W.; Thomas, G. E.; London, J. Bibcode: 1982GeoRL...9..587R Altcode: Beginning on October 13, 1981 a two channel spectrometer aboard the Solar Mesosphere Explorer has been obtaining daily measurements of full disc solar irradiance. These observations cover the spectral interval 120 to 305nm with ∽ .75nm spectral resolution. The relative accuracy of the measurements from day to day over the first three solar rotations is approximately 1%. In this report we present analyses of Lyman-alpha, the integrated Schumann-Runge continuum (130-175nm), and the integrated Schumann-Runge bands (175 to 190nm). All three show a clear variability related primarily to the 27-day solar rotation period. Correlations of these three values of solar irradiance to ground-based indices of solar activity, 10.7cm flux and sunspot number, are presented. Title: The solar spectral irradiance 1200-3184 Å near solar maximum: July 15, 1980 Authors: Mount, G. H.; Rottman, G. J. Bibcode: 1981JGR....86.9193M Altcode: Full-disk solar spectral irradiances near solar maximum were obtained in the spectral range 1200-3184 Å at a spectral resolution of approximately 1 Å from rocket observations above White Sands Missile Range, New Mexico, on July 15, 1980. Comparison with measurements made in 1979 and during solar minimum confirms a large increase at solar maximum in the solar irradiance near 1200 Å with no change within our measurement errors near 2000 Å. Irradiances in the range 1900-2100 Å are in excellent agreement with previous measurements, and those in the 2100- to 2500-Å range are lower than the Broadfoot results. We find agreement with previous values 2600-2900 Å and then fall below those values 2900-3184 Å. Title: Multi-anode microchannel arrays. Authors: Timothy, J. G.; Mount, G. H.; Bybee, R. L. Bibcode: 1981ITNS...28..689T Altcode: No abstract at ADS Title: The solar spectral irradiance 1200-2550 Å at solar maximum Authors: Mount, G. H.; Rottman, G. J.; Timothy, J. G. Bibcode: 1980JGR....85.4271M Altcode: Full-disk solar solar spectral irradiances at solar maximum were obtained in the spectral range 1200-2550 Å at a spectral resolution of approximately 1 Å from rocket observations above White Sands, New Mexico, on June 5, 1979. Comparison with measurements made near solar minimum indicates approximately a factor of 2.5 increase in the irradiance at 1200 Å, a 20% increase near 1800 Å, and no increase within our measurement errors (+/-15%) above 2100 Å. Irradiances in the range 1800-2100 Å are in excellent agreement with previous measurements, but those in the 2100- to 2550-Å range are significantly lower. The intensities of strong emission lines at wavelengths below 1850 Å are also reported. Title: The solar spectral irradiance 1200-3184 a near solar maximum, 15 July 1980 Authors: Mount, G. H.; Rottman, G. J. Bibcode: 1980STIN...8132107M Altcode: Full disk solar spectral irradiances near solar maximum were obtained in the spectral range 1200 to 3184 A at a spectral resolution of approximately 1 A from rocket observations above White Sands Missile Range. Comparison with measurements made during solar minimum confirm a large increase at solar maximum in the solar irradiance near 1200 A with no change within the measurement errors near 2000 A. Irradiances in the range 1900 to 2100 A are in excellent agreement with previous measurements, and those in the 2100 to 2500 A range are lower than separate previous results in this range. Agreement is found with previous values 2500 to 2900 A A, and then fall below those values 2900 to 3184 A. Title: The Multi-Anode Microchannel Array Detector System Authors: Timothy, J.; Mount, G.; Bybee, R. Bibcode: 1980oits.conf..733T Altcode: No abstract at ADS Title: Scientific objectives of the Solar Mesosphere Explorer mission Authors: Thomas, G. E.; Barth, C. A.; Hansen, E. R.; Hord, C. W.; Lawrence, G. M.; Mount, G. H.; Rottman, G. J.; Rusch, D. W.; Stewart, A. I.; Thomas, R. J. Bibcode: 1980PApGe.118..591T Altcode: The paper describes the NASA Solar Mesosphere Explorer mission which will study mesospheric ozone and the processes which form and destroy it, measure the ozone density and its altitude distribution from 30 to 80 km, monitor incoming solar UV radiation, and provide a rigorous test of the photochemical equilibrium theory of the mesospheric oxygen-hydrogen system. Five instruments will be carried on the polar-orbiting spacecraft: UV ozone, IR airglow, and visible NO2 programmable Ebert-Fastie spectrometers, a four-channel IR radiometer, and a solar UV spectrometer. Atmospheric measurements will be made of the mesospheric and stratospheric ozone density distribution, water vapor density distribution, temperature profile, ozone photolysis rate, and NO2 density distribution. In addition, the solar UV monitor will measure both the 0.2-0.31 micron spectral region and the Lyman-alpha (0.1216 micron) contribution to the solar irradiance. Title: Spatially Resolved Line Profiles of O III and He II in NGC-7662 and-7009 with the SPIFT-MAMA Authors: Smith, W. H.; Timothy, G.; Mount, G.; Snow, T. B. Bibcode: 1979BAAS...11..626S Altcode: No abstract at ADS Title: Vacuum ultraviolet spectrophotometry and effective temperatures of hot stars. Authors: Brune, W. H.; Mount, G. H.; Feldman, P. D. Bibcode: 1979ApJ...227..884B Altcode: Absolutely calibrated ultraviolet stellar spectra from 3100 A to the hydrogen absorption edge at 912 A were obtained on 1977 February 17 by rocket observations above Woomera, Australia. Spectra taken at 15 A resolution have been compared with the observed fluxes from OAO 2 and with recent model-atmosphere fluxes of Kurucz for five hot stars: Gamma (2) Vel, Zeta Pup, Alpha Eri, Beta Cen, and Alpha Vir. The present data give fluxes which are generally lower than those obtained from OAO 2, with the largest deviations of about 20% between 1400 and 1700 A. Agreement with the models is good, although the model fluxes are substantially larger than the observed values below 1200 A. This discrepancy is greater for the higher-temperature stars. Effective temperatures are also determined and are in good agreement with previous results. Title: The Status of the Multi-Anode Microchannel Arrays (MAMA) Detector Development Program Authors: Gethyn, Timothy J.; Mount, George H. Bibcode: 1979SPIE..172..199G Altcode: The Multi-anode Microchannel Arrays (MAMA's) are a family of photoelectric photon-counting array detectors being developed for use in instruments on both ground-based and space-borne telescopes. MAMA detectors can be operated in a windowless configuration at extreme-ultraviolet and soft x-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. Prototype MAMA detectors with up to 512 x 512 pixels are now being tested in the laboratory and telescope operation of a simple (10 x 10)-pixel visible-light detector has been initiated. In this paper the methods of construction and the modes of operation of the MAMA detectors are described and the status of the development program is reviewed. Title: Detector arrays for photometric measurements at soft X-ray, ultraviolet and visible wavelengths Authors: Timothy, J. G.; Mount, G. H.; Bybee, R. L. Bibcode: 1979SPIE..183..169T Altcode: The construction and modes of operation of the Multi-Anode Microchannel Array (MAMA) detectors are described, and the designs of spectrometers utilizing them are outlined. MAMA consists of a curved microchannel array plate, an opaque photocathode (peak quantum efficiency of 19% at 1216 A), and a multi-anode (either discrete- or coincidence-anode) readout array. Designed for use in instruments on spaceborne telescopes, MAMA can be operated in a windowless configuration in extreme-ultraviolet and soft X-ray wavelengths, or in a sealed configuration at UV and visible wavelengths. Advantages of MAMA include low applied potential (less than 3.0 kV), high gain (greater than 10 to the 6th electrons/pulse), low sensitivity to high-energy charged particles, and immunity to external magnetic fields of less than 500 Gauss Title: Multi-anode microchannel arrays Authors: Timothy, J. G.; Mount, G. H.; Bybee, R. L. Bibcode: 1979SPIE..190..360T Altcode: The Multi-Anode Microchannel Arrays (MAMA's) are a family of photoelectric, photon-counting array detectors being developed for use in instruments on both ground-based and space-borne telescopes. These detectors combine high sensitivity and photometric stability with a high-resolution imaging capability. MAMA detectors can be operated in a windowless configuration at extreme-ultraviolet and soft X-ray wavelengths or in a sealed configuration at ultraviolet and visible wavelengths. Prototype MAMA detectors with up to 512 x 512 pixels are now being tested in the laboratory and telescope operation of a simple (10 x 10)-pixel visible-light detector has been initiated. The construction and modes-of-operation of the MAMA detectors are briefly described and performance data are presented. Title: Comprehensive analysis of gratings for ultraviolet space instrumentation Authors: Mount, G. H.; Fastie, W. G. Bibcode: 1978ApOpt..17.3108M Altcode: Comprehensive measurements in the vacuum UV range of 1200-3000 A of efficiency, polarization, and scattering of classically ruled and photoresist gratings are reported. The results show that the art of ruling gratings for vacuum UV use has reached a high level of sophistication and that careful analysis of grating properties can lead to useful improvement of the ruling art. Title: A search for far-ultraviolet emission from Sirius B. Authors: Brune, W. H.; Feldman, P. D.; Mount, G. H. Bibcode: 1978ApJ...225L..67B Altcode: A rocket observation of Sirius in the far-UV region from 912 to 1240 A is reported. It is found that only a few counts were detected which can possibly be attributed to the hydrogen-rich white dwarf Sirius B. An upper limit of 2.0 by 10 to the -10th power erg/sq cm per sec/A on the Sirius B flux in the range from 1000 to 1080 A is established with 99.3% confidence. This upper limit is shown to constrain the model-dependent effective temperature of Sirius B to be less than or approximately 27,000 K. It is concluded that the observed X-ray flux from Sirius cannot be emitted by the photosphere of Sirius B. Title: Photoabsorption cross sections of methane and ethane, 1380 - 1600 Å, at T = 295K and T = 200K. Authors: Mount, G. H.; Moos, H. W. Bibcode: 1978ApJ...224L..35M Altcode: Photoabsorption cross sections of methane and ethane have been determined in the wavelength range from 1380 to 1600 A at room (295 K) and dry-ice (200 K) temperatures. It is found that the room-temperature ethane data are in excellent agreement with the older measurements of Okabe and Becker (1963) rather than with more recent determinations and that a small systematic blueshift occurs at the foot of the molecular absorption edges of both gases as the gases are cooled from room temperature to 200 K, a value close to the actual temperature of the Jovian atmosphere. It is concluded that methane photoabsorption will dominate until its cross section is about 0.01 that of ethane, which occurs at about 1440 A, and that ethane should be the dominant photoabsorber in the Jovian atmosphere in the region from above 1440 A to not farther than 1575 A. Title: Continuum Modeling of Ultraviolet Rocket Spectra (900-3100 Å Five Early-Type Stars. Authors: Mount, G. H.; Brune, W. H.; Feldman, P. D. Bibcode: 1977BAAS....9..570M Altcode: No abstract at ADS Title: Photoabsorption cross section of methane from 1400 to 1850 Å. Authors: Mount, G. H.; Warden, E. S.; Moos, H. W. Bibcode: 1977ApJ...214L..47M Altcode: Photoabsorption cross sections of methane in the 1400-1850-A spectral region have been measured. Cross sections at wavelengths greater than 1475 A are approximately 200 times smaller than those currently accepted. This has a significant effect on the interpretation of spectral measurements of the Jovian planets in this wavelength region. Title: Compact far ultraviolet emission source with rich spectral emission 1150-3100 &Aring Authors: Mount, George H.; Yamasaki, G.; Fowler, Walter; Fastie, William G. Bibcode: 1977ApOpt..16..591M Altcode: The article describes a compact hollow Pt cathode emission source for the far UV, developed for use as a high-resolution wavelength standard in laboratory work or on spacecraft (specifically, the NASA International UV Explorer - IUE). The source is small, rugged, lightweight, spectrally rich, bright in the 1150-3200 A region, features long service life, low operating voltage, and lower power drain, and stably emits a large number of very sharp lines with a spectrum lending itself to projection onto the focal plane of a spectrograph. The source has successfully passed exacting environmental tests, and serves as a transfer standard for absolute sensitivity calibration of spectrometric instruments. Title: Moderate Resolution Ultraviolet Rocket Observations 912-3100 Å of Seven Early-Type Stars. Authors: Brune, W. H.; Mount, G. H.; Feldman, P. D. Bibcode: 1977BAAS....9..366B Altcode: No abstract at ADS Title: A new solar carbon abundance based on non-LTE CN molecular spectra. Authors: Mount, G. H.; Linsky, J. L. Bibcode: 1975ApJ...202L..51M Altcode: A detailed non-LTE analysis of solar CN spectra strongly suggest a revised carbon abundance for the sun. We recommend a value of log carbon abundance = 8.35 plus or minus 0.15 which is significantly lower than the presently accepted value of log carbon abundance = 8.55. This revision may have important consequences in astrophysics. Title: A non-LTE analysis of the CN 3883 Å band head in the upper photosphere of Arcturus. Authors: Mount, G. H.; Ayres, T. R.; Linsky, J. L. Bibcode: 1975ApJ...200..383M Altcode: A detailed non-LTE study of the CN(0,0) 3883 A band-head spectrum of Arcturus (K2 iii) provides an accurate determination of the carbon, nitrogen, and oxygen abundances in Arcturus. Non-LTE effects are significant, and we find that the Ayres-Linsky model provides an adequate fit to the observations for [C,N]* = 13[C,N]0 and [O]* = 0.60[0]o, or for [C,N,O]* = 16[C,N,O]0, but the latter abundances are unlikely. The upper photospheric microturbulence is found to be 2.5 + . Subject headings: abundances, stellar - atmospheres, stellar - late-type stars - molecules - stars, individual (alpha Boo) Title: One- and Multi-Component Models of the Upper Photosphere Based on Molecular Spectra. IV: Non-LTE Treatment of the CN Violet System Authors: Mount, G. H.; Linsky, J. L. Bibcode: 1975SoPh...41...17M Altcode: Non-LTE synthetic spectra derived from a detailed analysis of the formation of the CN (0, 0) λ13883 Å spectrum are compared with center-limb photoelectric spectra taken at Kitt Peak National Observatory.1 Significant non-LTE effects are found and the Kurucz, Altrock-Cannon, Mount-Linsky II, and HSRA models are compared. We derive a solar carbon abundance of Ac=8.30±0.10 for the Mount-Linsky model and Ac=8.40±0.10 for the Altrock-Cannon model, compared to the HSRA value of Ac=8.55±0.10, assuming a nitrogen abundance of logAN=7.93. In addition we specify the regions of formation for the CN(0, 0) 3883.35 Å bandhead at disc center and limb. Title: Models of the upper photospheres of the Sun and Arcturus based on molecular spectra Authors: Mount, George Henry Bibcode: 1975PhDT.......265M Altcode: No abstract at ADS Title: Models of the Upper Photospheres of the Sun and Arcturus Based on Molecular Spectra. Authors: Mount, G. H. Bibcode: 1975PhDT.........5M Altcode: Accurate photoelectric center limb spectra of the solar CN and CH molecules and CN spectroheliograms were obtained. These observations, together with observations of the solar CO fourth positive EUV system and the Griffin Arcturus Atlas, were compared with theoretical LTE and non-LTE spectra of CN, CH, and CO in the Sun and CN in Arcturus (K2 III). The molecular line source functions deviate significantly in all cases from the Planck function, and thus it was found that non-LTE effects are critical in interpreting molecular spectra in the Sun and Arcturus. Data also show that the solar photospheric model based on CN, CH, and CO spectra gives better agreement with observation. Both LTE and non-LTE CN and CH analyses demonstrate that the presently assumed value of the solar carbon abundance must be significantly reduced. Title: Non-LTE Models of the Upper Solar Photosphere Based on CN Molecular Spectra Authors: Mount, G. H.; Linsky, J. L. Bibcode: 1974BAAS....6Q.347M Altcode: No abstract at ADS Title: One- and Multi-Component Models of the Upper Photosphere Based on Molecular Spectra. III: CH (0, 0) λ 3144 of the CH C-X System Authors: Mount, George H.; Linsky, Jeffrey L. Bibcode: 1974SoPh...36..287M Altcode: We have obtained accurate center-to-limb photoelectric spectra of the CH (0, 0) C-X bandhead region λ3143-3148 Å at Kitt Peak National Observatory. From these spectra and a detailed analysis of the formation of the CH (0, 0) spectrum we demonstrate that the best-fit upper photospheric model derived from our previous analyses of CN (0, 0) and CN (1, 1) spectra adequately explains the CH C-X observations. In addition we derive a solar carbon abundance of ±0.20 compared to the HSRA value of log Ac = 8.55. This confirms our previous CN analyses which demonstrated that if the HSRA nitrogen abundance of log AN = 7.93 ± 0.10 is assumed, then log Ac = 8.20 ± 0.10. We also specify the regions of formation for the CH(0, 0) λ3143.47 Å band-head at disc center and limb. Title: One- and Multi-Component Models of the Upper Photosphere Based on Molecular Spectra. II: CN (1, 1) of the CN Violet System Authors: Mount, George H.; Linsky, Jeffrey L. Bibcode: 1974SoPh...35..259M Altcode: We have obtained center-to-limb photoelectric spectra of the CN(1,1) B-X bandhead region λ3868-3872 Å at Kitt Peak National Observatory. From these spectra and a detailed analysis of the formation of the CN (1, 1) spectrum we derive a best-fit upper photospheric model differing from the HSRA which is consistent with our previous CN(0, 0) λ3883 spectra. We derive a solar carbon abundance of log Ac = 8.30 ± 0.10 compared to the HSRA value of log Ac = 8.55 ± 0.10. In addition we specify the regions of formation for the CN(0, 0) λ3883.35 and CN(1, 1) λ 3871.38 bandheads at disc center and limb. Title: Models of the Upper Solar Photosphere Based on CN and CH Molecular Spectra. Authors: Mount, G. H.; Linsky, J. L. Bibcode: 1973BAAS....5..444M Altcode: No abstract at ADS Title: One- and Multi-Component Models of the Upper Photosphere Based on Molecular Spectra. I: The Violet System of CN(0,0) Authors: Mount, George H.; Linsky, Jeffrey L.; Shine, Richard A. Bibcode: 1973SoPh...32...13M Altcode: Spectroheliograms taken in the CN(0, 0) violet band near λ 3883 Å show very small scale network and cell structures with high contrast. The bandhead itself, which is a broad feature due to overlap of several CN lines, allows the diagnostic simplicity of a continuum since motions, magnetic fields, and broadening mechanisms are unimportant. We have obtained spectroheliograms in the bandhead and center-to-limb photoelectric spectra of CN(0, 0) at Kitt Peak National Observatory. From the photoelectric spectra and a detailed analysis of the formation of the CN(0, 0) spectrum we derive a best-fit one-component upper photospheric model differing from that of the HSRA and recommend a change in solar carbon abundance from the HSRA value of logAc = 8.55 to logAc = 8.25. From the calibrated spectroheliograms we consider a multi-component model to account for the observed fine structure intensity variations. Title: One- and Multi-Component Models of the Upper Photosphere based on the 3883 Å Band Head of CN Authors: Mount, George H.; Linsky, Jeffrey L. Bibcode: 1973BAAS....5V.277M Altcode: No abstract at ADS Title: On the validity of a generalized Kirchhoff's law for a nonisothermal scattering and absorptive medium Authors: Linsky, Jeffrey L.; Mount, George H. Bibcode: 1972Icar...17..193L Altcode: The relationship of directional hemispherical reflectivity to emissivity is investigated for a nonisothermal medium with isotropic coherent scattering and absorption. Departures from a generalized Kirchhoff's Law occur due to the long range nature of the scattering process. Such departures occur in lunar thermal emission at microwave but not at infrared frequencies.