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High‐Latitude Observations of a Localized Wind Wall and Its Coupling to the Lower Thermosphere
Author(s) -
Shepherd Gordon G.,
Shepherd Marianna G.
Publication year - 2018
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl077722
Subject(s) - thermosphere , geology , latitude , longitude , atmospheric sciences , atmosphere (unit) , global wind patterns , divergence (linguistics) , ionosphere , geophysics , geodesy , climatology , meteorology , physics , linguistics , philosophy
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° and 70°. These are confined to a narrow region between 100° and 200° 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( 1 S) emission rate. They are present about one half of the time in local summer and autumn.