资源环境科技发展态势分析平台

Reversals in the thermospheric zonal winds at altitudes of 140 to 250 km from eastward to westward have been found at southern geographic latitudes between 60 degrees and 70 degrees. These are confined to a narrow region between 100 degrees and 200 degrees in longitude with zonal velocities regularly of -400 m/s, sometimes reaching -600 m/s, so sharply defined that the authors describe it as a "wind wall." The observations were made by the Wind Imaging Interferometer on National Aeronautics and Space Administration's Upper Atmosphere Research Satellite, and they occur as the field of view crosses the high polar cap wind field. The wind reversals at the wall boundaries create a convergence on the west side of the wall and a divergence on the east side that potentially generate vertical flows, consistent with observed perturbations in the O(S-1) emission rate. They are present about one half of the time in local summer and autumn.