Abstract
Optical Doppler observations of the thermospheric wind are reported for 8 and 9 December 1981. These were obtained simultaneously from Longyearbyen (78.2°N, 15.6°E) and Kiruna (67.8°N, 20.0°E) using the 630 nm red airglow emission from atomic oxygen as a tracer. The source has a layer width of approximately 50 km and an optical center at a height of about 240 km. Meridional winds in the midnight sector from the two stations show a similarity in pattern and magnitudes which is consistent with the indicated passage of air parcels almost in a direct path between the stations. The zonal winds show some differences, which are most marked in the dusk and dawn sectors, indicating non-uniformity of flow consistent with the presence of dawn and dusk vortices. These would be expected due to the tendency of the thermospheric wind to conform to the gross features of the ion convection pattern, which was presumed to have a twin cell form for the IMF B z negative conditions existing. Comparison of the data with the time-dependent thermospheric model of Fuller-Rowell and Rees is good for the meridional components, but poorer for the zonal winds. The meridional winds match in magnitude, gradient and zero crossings. It is suggested that the poorer prediction of the zonal components is due to a combination of two factors: the difference between the actual auroral conditions and those used as inputs to the model, and the absence, in the model, of asymmetries due to IMF B y effects in the convection pattern.
Published Version
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