Delayed response of the ionosphere to solar EUV variabilities

Abstract

The ionospheric plasma reacts on solar EUV and UV variations with a time delay of 1-2 days. This delay is assumed to be owing to thermospheric transport processes from the lower ionosphere to the F region, but only limited modeling has been performed so far to prove this hypothesis. Here we will present first results of the ionospheric delay based on a comprehensive and reliable data base on assimilated TEC model and EUV spectral flux data. We specify the various dependencies from geographic/geomagnetic location, altitude, season, local time, geophysical and solar radiation conditions such as the solar activity level. These first results can provide more insight into ionospheric processes and are of interest for ionospheric applications in forecasting ionospheric weather, e.g. for the use in GNSS error analyses and predictions.