Solar cycle variation of nitric oxide in the thermosphere

The measurements of trace gases in the atmosphere made by the Halogen Occul tation Experiment instrument on UARS have been used to investigate the sola r cycle variation of nitric oxide. The data covers the period from near sol ar activity maximum in late 1991 to its near minimum in late 1996. Systemat ic errors in the NO measurements were corrected, and the results were corre lated with the F-10.7 index. Regression coefficients derived from this anal ysis are presented. It is found that nitric oxide in the equatorial thermos phere varies significantly with F-10.7 but its variation in polar thermosph ere is very small.