JNO2 at high solar zenith angles in the lower stratosphere

In situ measurements of NO, NO2, O3, HO2, ClO, pressure, and temperature have been made at high solar zenith angles (SZA, 70°–93°) in the lower stratosphere. These measurements are used to derive the photolysis rate of NO2, JNO2, using a time-dependent method. The resultant JNO2 values and the results of a multiple-scattering actinic flux model show a linear relationship throughout the SZA range. The difference of the two sets of JNO2 values of about 11% suggests that the model scattering calculation is very accurate at high SZA conditions near sunrise and sunset.