For realistic predictions of global thermospheric dynamics using thermospheric general circulation models (TGCMs), one of the main problems lies in the specification of the three-dimensional, time-dependent forcing fields for any given day. The Equinox Transition Study (ETS) interval was simulated using the National Center for Atmospheric Research TGCM with inputs guided by observations. During the ETS campaign, large quantities of high-quality data were available from high latitudes, and the high-latitude ...