Solar EUV flux, exospheric temperature and thermospheric wind inferred from incoherent scatter measurements of the electron density profile at Millstone Hill and Shigaraki

Abstract

We explore a method for inferring solar EUV flux, atmospheric composition and wind using ionospheric electron density Ne profile measurements. Incoherent scatter radar data from Millstone Hill and Shigaraki measured on October 5, 1989 are assimilated into a theoretical model whose driving forces, solar EUV flux, exosphere temperature Tex, and meridional wind, are adjustable. Adjustments are made to give best match between the model Ne profile and the data. The derived Tex values, found to be low near noon at Millstone and high in the afternoon at Shigaraki, are essentially those required to give the [O]/[N2] ratio necessary to fit the data. Our inferred EUV fluxes for the two sites are similar. Our technique of using profile data may resolve the ambiguity in deriving EUV and [O]/[N2] from electron‐density measurements.