CHEMISTRY

Syntax:

CHEMISTRY OH eeee eeee [PRESSURE eeee]

Where eeee are floating point numbers (respectively a, b, and c). Only the chemical destruction of the tracer by monthly averaged OH fields has been implemented. The rate of destruction is determined by the reaction:

Tracer + OH ----> products

With d(Tracer)/dt = -k*OH*Tracer, k being the rate constant given in cm³s^-1.

Concentrations are assumed in number density (cm^-3).

k is calculated from k = a exp( b/T) * (1 + c.PRESSURE) with

a in cm^-3

b in Kelvin (temperature dependence)

c in 1/bar (pressure dependence)

The tracer destruction is calculated from k and the OH fields (which are read in monthly).

Examples:

The pressure dependent destruction of CO by OH is activated by:

CHEMISTRY OH 0.15e-12 0.0 PRESSURE 0.06

The destruction of methylchloroform by OH is given by:

CHEMISTRY OH ???? -1550.0 (??? determined in exercise 9)

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