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Changes of thermospheric composition and ionospheric density caused by quasi 2 day wave dissipation
Author(s) -
Yue Jia,
Wang Wenbin
Publication year - 2014
Publication title -
journal of geophysical research: space physics
Language(s) - English
Resource type - Journals
eISSN - 2169-9402
pISSN - 2169-9380
DOI - 10.1002/2013ja019725
Subject(s) - thermosphere , ionosphere , atmospheric sciences , middle latitudes , physics , atmosphere (unit) , mixing ratio , computational physics , geophysics , meteorology
Using the thermosphere‐ionosphere‐mesosphere electrodynamics–general circulation model, we investigate the effect of quasi 2 day wave (QTDW) dissipation on thermospheric composition (O/N 2 ) and ionospheric electron density during solar minimum. The overall thermospheric and ionospheric changes induced by the QTDW are evaluated by running the model with and without QTDW forcing imposed at the model lower boundary. The dissipation of the westward propagating QTDW in the lower thermosphere causes westward mean wind acceleration and drives a poleward meridional circulation. The circulation induced by the QTDW, as determined by the difference between the mean wind patterns of a run with the QTDW and a base run without the QTDW, enhances the mixing of constituents in the lower thermosphere. Through molecular diffusion, the decrease of the O mixing ratio and the increase of the N 2 and O 2 mixing ratios propagate from the lower thermosphere into the upper thermosphere. As a result, the O/N 2 ratio near the ionospheric F 2 peak is reduced by about 16–20% at low and midlatitudes. This in turn produces an approximately 16–32% depletion in the F 2 peak electron density at low and midlatitudes. The simulated decrease of electron density during a QTDW event is in quantitative agreement with published observations. This work suggests a new major pathway for the traveling planetary wave from the lower atmosphere to affect the thermosphere and ionosphere via dissipation and mean wind acceleration.