Articles | Volume 27, issue 2
Ann. Geophys., 27, 831–837, 2009
https://doi.org/10.5194/angeo-27-831-2009
Ann. Geophys., 27, 831–837, 2009
https://doi.org/10.5194/angeo-27-831-2009

  19 Feb 2009

19 Feb 2009

The influence of geomagnetic activity on mesospheric summer echoes in middle and polar latitudes

O. Zeller1,2 and J. Bremer1 O. Zeller and J. Bremer
  • 1Leibniz-Institute of Atmospheric Physics, 18225 Kühlungsborn, Schloss-Str. 6, Germany
  • 2Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH, UK

Abstract. The dependence of mesospheric VHF radar echoes during summer months on geomagnetic activity has been investigated with observation data of the OSWIN radar in Kühlungsborn (54° N) and of the ALWIN radar in Andenes (69° N). Using daily mean values of VHF radar echoes and of geomagnetic activity indices in superimposed epoch analyses, the comparison of both data sets shows in general stronger radar echoes on the day of the maximum geomagnetic activity, the maximum value one day after the geomagnetic disturbance, and enhanced radar echoes also on the following 2–3 days. This phenomenon is observed at middle and polar latitudes and can be explained by precipitating particle fluxes during the ionospheric post storm effect. At polar latitudes, the radar echoes decrease however during and one day after very strong geomagnetic disturbances. The possible reason of this surprising effect is discussed.