SOLAR ATMOSPHERIC COUPLING BY ELECTRONS (SOLACE) 2 - CALCULATED STRATOSPHERIC EFFECTS OF PRECIPITATING ELECTRONS, 1979-1988

An analysis has been carried out of the effects of energetic electron precipitation (EEP) on stratospheric NOy, NO2, and O-3. Solar wind obs ervations used together with precipitating electron fluxes observed ab oard TIROS spacecraft show a close relationship between the long- and short-term fluctuations in the solar wind and EEP over a period of 16 years. Daily electron energy spectra for 4.25 less than or equal to E less than or equal to 1050 keV and energy deposition profiles are deve loped for both hemispheres for L greater than or equal to 5 and used i n two-dimensional chemical transport simulations for the period Januar y 15, 1979, through December 31, 1987. Results indicate that globally averaged column NOy (from 25 to 40 km) increases by approximate to 12% between 1979 and 1983-1985 with a rapid decline to 1979 levels betwee n early 1985 and 1987. Day-by-day comparisons of the results with the Stratospheric Aerosol and Gas Experiment (SAGE II) column NO2 and O-3 for the period October 24, 1984, and December 31, 1987, show good agre ement with the inclusion of EEP in the simulations. Northern near-hemi spheric decreases of column NO2 of approximate to 35% observed by SAGE II between early 1985 and 1987 are well simulated with the inclusion of EEP. Comparisons of several simulations with one another and with S AGE II: NO2 data and Solar Backscattered Ultraviolet (SBUV) (V6) O-3 d ata suggest that SOLACE represents a solar- terrestrial coupling mecha nism which, for solar cycle 21, is as important to stratospheric O-3 a s solar UV flux variations.