ASTRA - Atmospheric & Space Technology Research Associates, LLC

Earth TIME-GCM

Effect of IMF-B Y on Thermospheric Composition at High and Mid Latitudes

We have used the versatile TIME-GCM to predict the response of thermospheric density and composition to changes in the interplanetary magnetic field (IMF). We already knew that the density and composition respond to the high latitude convection pattern, which has a strong dependence on the Y-component (B Y ) of the IMF. Therefore we expected the B Y to drive corresponding changes in the density and composition.

We found that the effect of changing from B Y -negative to B Y -positive is a clockwise rotation of both the density (left-hand column) and column-integrated O/N 2 ratio patterns (right-hand column). In addition, the left-hand column reveals how the relative sizes of the dawn and dusk neutral density cells hange in response to the sign of B Y . These results were published in Crowley et al. (2006). In a companion paper we also performed a more realistic study, comparing model results with images from the DE-1 satellite (Immel et al., 2006).

This material is based upon work supported by the National Science Foundation under Grant No. 0332307.  Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).