EFFECT OF SOLAR PROTON EVENTS ON THE MIDDLE ATMOSPHERE DURING THE PAST 2 SOLAR-CYCLES AS COMPUTED USING A 2-DIMENSIONAL MODEL

Daily average solar proton flux data for the years 1963-1984 (two solar cycles) have been used in a proton energy degradation scheme to derive ion pair production rates and, subsequently, HOx(H, OH, HO2) and NOx(N, NO, NO2) production rates. These HOx and NOx production rates are computed in a form suitable for inclusion in an atmospheric two-dimensional time-dependent photochemical model. The HOx increases, although large for certain solar proton events (SPEs), are relatively short-lived because the HOx species have lifetimes of only hours in the middle atmosphere. For longer-lived NOx species, increases are important for 2-4 months past the more intense SPEs but are generally negligible 6 months after the SPE. -from Authors