Laboratory studies on the stratospheric NOx production rate

The chemistry of the production of NO in the stratosphere was examined in a two part study. First, the absolute quantum yield for the production of NO( 2 Π) + N( 4 S) from N 2 O photolysis at 193 run was measured to be less than 8×10 −3 . Second, in a new type of experiment, the yields of NO from the photolysis of N 2 O at 193 nm in N 2 O/O 2 /N 2 and the photolysis of O 3 at 248 nm in O 3 /N 2 O/O 2 /N 2 mixtures were measured. The measured yields showed excellent agreement with NO yields predicted from a model using previously measured rate parameters. The results of this “integrated” experiment reduced the most probable uncertainty in the yield of NO from near 80% (calculated from the uncertainties in each individual step) to less than 30%.