Actinic flux and photolysis frequency comparison computations using the model PHOTOGT

The accurate radiative transfer model GOMETRAN, initially designed to yield radiances at TOA in the wavelength range 240-790 nm, has been extended to allow for the computation of actinic fluxes down to 175 nm and for the calculation of photolysis frequencies in the atmosphere. The capability of the extended model PHOTOGT (PHOTOGOMETRAN) is demonstrated in a number of successful comparison studies both with recent experiments (ground-based, balloon-borne, airborne) and model calculations of radiances, actinic fluxes and photolysis frequencies in the stratosphere and troposphere. In an atmospheric case study, the impact of new quantum yield data for the O-3 --> O-2 + O(D-1) photodissociation channel on the photolytic production of O(D-1) atoms in the lower atmosphere has been quantified.