Effects of High Latitude Forcing on the Thermosphere
ASTRA is using the TIME-GCM model to investigate the formation mechanisms of cellular structures (discovered by Crowley et al. 1989) in the thermospheric neutral density at high latitudes. Dr. Crowley has worked to understand the cells since their discovery and has published several results on their behavior during solar minimum and maximum, and has confirmed their existence in satellite data.
The figure shows changes in the neutral density cell structure predicted by the TIME-GCM as the Joule heating and momentum forcing are varied in a controlled manner. We find that increasing the Joule heating increases the background density, but does not affect the density cell structure significantly. In contrast, increasing the momentum forcing amplifies the cell structure. This suggests the momentum forcing is much more important than Joule heating in producing the cells. We are developing special model post-processors to further analyze the density response.
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).