High latitude thermospheric circulation during the Energy Budget Campaign

Presented is an analysis of the thermospheric wind data obtained using a Fabry-Perot interferometer during 16 nights of observation from Esrange as part of the Energy Budget Campaign. The OI 630 emission line observations in conjunction with a global theoretical dynamical model of the thermosphere indicate that the systematic behavior of thermospheric winds, as seen from Kiruna, northern Sweden, is that of a poleward daytime wind which evolves into a nearly ubiquitous equatorward wind between 1600 and 0300 UT. It is also noted that for the same ground-level magnetic disturbance at Kiruna, western (evening) winds exceed eastern (morning) winds by a factor of 2. Finally, it is reported that there were three occasions in the 16-night period on which the local input during a substorm was sufficient to halt or temporarily reverse a preexisting equatorward wind of 300 m/s.