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Detailed Reference Information |
Herrero, F.A. and Meriwether, J.W. (1994). The 630 nm MIG and the vertical neutral wind in the low latitude nighttime thermosphere. Geophysical Research Letters 21: doi: 10.1029/93GL03115. issn: 0094-8276. |
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It is shown that large negative divergences (gradients) in the horizontal neutral wind in the equatorial thermosphere can support downward neutral winds in excess of 20 m/s. With attention to the meridional and vertical winds only, the pressure tendency equation is used to derive the expression Uz0≈〈∂Uy/∂y〉H for the vertical wind Uz0 at the reference altitude for the pressure tendency equation; H is the atmospheric density scale height, and 〈∂Uy/∂y〉 is the meridional wind gradient. The velocity gradient associated with the Meridional Intensity Gradient (MIG) of the O(1D) emission (630 nm) at low latitudes is used to estimate the vertical neutral wind in the MIG region. Velocity gradients derived from MIG data are about 0.5 (m/s)/km or more, indicating that the MIG region may contain downward neutral winds in excess of 20 m/s. Though direct measurements of the vertical wind are scarce, Fabry--Perot interferometer data of the equatorial F-region above Natal, Brazil, showed downward winds of 30 m/s, occurring during a strong meridional wind convergence in 1982. In situ measurements with the WATS instrument on the DE-2 satellite also show large vertical neutral winds in the equatorial region. ¿ American Geophysical Union 1994 |
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Abstract |
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Keywords
Meteorology and Atmospheric Dynamics, Thermospheric dynamics, Ionosphere, Equatorial ionosphere, Ionosphere, Ionosphere-atmosphere interactions, Atmospheric Composition and Structure, Airglow and aurora |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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