Study of the delayed ionospheric response to solar EUV

Abstract

Physical and chemical processes in the ionosphere are driven by complex interactions of the neutral and ionized atmospheric constituents with the solar radiation. The ionospheric plasma is in particular sensitive to solar EUV and UV variations with a time delay between one and two days. This delay is assumed to be related to thermospheric transport processes from the lower ionosphere to the F region. In previous analyses, the delay has been investigated using the F10.7 index. Here we present preliminary analyses of the ionospheric delay based on a comprehensive and reliable database consisting of GNSS TEC maps and EUV spectral flux data. We plan to specify the various dependencies of the delay on geographic/geomagnetic location, altitude, season, local time, geophysical, and solar radiation conditions such as the solar activity level. We will present first results for the seasonal and EUV wavelength region dependency of the ionosphere. These results can provide more insight into ionospheric processes and are of interest for applications depending on reliable ionospheric weather forecasts, e.g. GNSS error analyses, prediction and mitigation.