Greifswald 2009 – wissenschaftliches Programm

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EP: Fachverband Extraterrestrische Physik

EP 2: Near Earth Space

EP 2.3: Vortrag

Montag, 30. März 2009, 15:00–15:15, Zahnklinik

Response of the upper mesosphere on solar proton events after radar observations at high, middle and low latitudes — •Ralph Latteck, Werner Singer, and Peter Hoffmann — Leibniz-Institut für Atmosphärenphysik, Schlossstr. 6, 18225 Kühlungsborn

The mesospheric response on severe solar activity storms with strongly enhanced proton fluxes and X/M-class X-ray flares in the period July 2000 to December 2006 has been studied in detail using meteor radar and MF radar observations at latitudes between 69°N and 22°S. Neutral air temperatures at mesopause heights are mostly decreased by 5-10 K during these events compared to undisturbed conditions. At the same time a lowering of the peak altitude of the meteor layer by about 500 m to 1000 m is observed. The change of the peak altitude of the meteor layer results from the burn off of the meteoroids at lower heights due to reduced air density. The height change is well correlated with the observed decrease of the mesopause temperature. Particular attention is devoted to the events in October 2005, January 2005, and December 2006 in respect to changes of the background wind field. The observations are discussed in relation to model results obtained for the events under study. Furthermore the variability of mean winds in relation to solar activity is discussed on the basis of on long-term observations of mesospheric winds at mid-latitudes.