Photochemistry of Atmospheric Trace Gases

Abstract

The complex scheme of atmospheric radical chain reactions is driven by a relatively small number of photodissociation processes. The most important ones in the troposphere are the formation of O( 1 D) by the photolysis of ozone (frequency J 1 ), and the photolysis of NO 2 (frequency J 2 ). It is shown that uncertainties in J 1 and J 2 lead to large uncertainties in model‐predicted species concentrations, particularly in OH levels. Methods of calculating/measuring J 1 and J 2 will be discussed.