Solar-atmospheric coupling by electrons (SOLACE) 3. Comparisons of simulations and observations, 1979-1997, issues and implications

Several middle atmospheric simulations have been carried out from January 1 979 to December 1997 including most effects important to stratospheric O-3 Results of these simulations for several species and species ratios have be en compared in detail with observations made by the Halogen Occultation Exp eriment, the Polar Ozone and Aerosol Measurement II, the Total Ozone Mappin g Spectrometer, the Jet Propulsion Laboratory Mark IV Interferometer, and d uring the Photochemistry of Ozone Loss in the Arctic Summer mission. For th e simulation including all effects, comparisons of all species and ratios s how excellent agreement. Comparisons of simulated sunset NO2 with and witho ut the effects of energetic electron precipitation show excellent agreement with observations with the effects of the electrons included but poor agre ement when they are excluded. The validated simulations indicate that the e ffects of a polar source of NOy must be included for an adequate simulation of stratospheric O-3 and NOy. A comparison of simulations, during the 11-y ear solar cycle, of the relative effects on O-3 of-solar UV flux variations and the energetic electron precipitation has been made. For global total O -3 the effects are comparable. For the global column above 25 km, the effec ts of energetic electron precipitation are significantly larger. The implic ations of, and some issues raised by, these findings are briefly discussed.