The Relative Influence of Solar Radiative and Solar Geomagnetic Variation on the Dynamics of the Polar Upper Mesosphere

Abstract

Resent research indicates that there might be a connection between perturbation of the Earth's geomagnetic field caused by solar wind, and the atmospheric circulation. In this project the mesospheric meridional and zonal wind, obtained from the SuperDARN radars Goose Bay, Hankasalmi, Kapuskasing, King Salmon, Kodiak, Pykkvibær, Saskatoon and Stokkseyri in the northern hemisphere was compared with the global Ap index along with the measure for solar radiance, the F10.7 index. Wind data from the SuperDARN radars were available for every hour and geomagnetic and irradiance data for every month. The solar atmospheric tides along with seasonal effects were removed from the wind data and the perturbation of the residual wind due to Ap and F10.7 was used to see if any connection between the mesospheric wind and Ap/F10.7 could be found, and if they influenced the wind in a similar manner. A tendency for more equatorwards and eastwards winds during periods of high geomagnetic activity was found. In addition, this effect was observed to increase with increasing geomagnetic latitude for the zonal wind. Ap and F10.7 often affected the wind in a similar manner, making it hard to distinguish the two. Using linear regression, the correlation between them was found to be high over the timescales of this study.