O3 → O(¹D) photolysis frequencies determined from spectroradiometric measurements of solar actinic UV‐radiation: Comparison with chemical actinometer measurements

Abstract

The solar actinic flux has been measured directly and spectrally resolved between 280 nm and 330 nm by means of a spectroradiometer. From these measurements the photolysis frequency J(O¹D) of ozone is calculated using ozone absorption cross‐sections and O(¹D) quantum yields from the literature. Different published wavelength dependencies of the O(¹D) quantum yield data are used to compare the spectroradiometric J(O¹D) values to J(O¹D) data measured simultaneously with a chemical actinometer. This field comparison supports laboratory studies that have measured O(¹D) quantum yields of about 0.2 to 0.3 between 315 nm and 320 nm. Implications for tropospheric photochemistry are discussed.