Popis: |
Precipitating energetic particles can penetrate into the low-altitude ionosphere and alter the ionization rate. Enhanced ionization in the D-region caused by energetic particle precipitation (EPP) affects cosmic radio signal absorption in the ionosphere. This impact is monitored by a Canadian network of wide-beam passive radio receivers, or riometers, to study precipitation-induced variations in the D-region ionosphere remotely. In this study, we examine the relationship between the background ionospheric profiles and absorption during a precipitation event observed by one of the POES satellites in conjunction with the Gillam riometer station (56N, 95W). We use different chemistry models to model the D-region ionosphere and investigate the effect of changing the chemistry model in an absorption event. We compare modelled absorption with ground-based measurements to discuss possible reasons for any discrepancy. |