TitleImpact of the lower thermospheric winter-to-summer residual circulation on thermospheric composition
Publication TypeJournal Article
Year of Publication2017
AuthorsQian, L, Yue, J
JournalGeophysical Research Letters
Pagination3971 - 3979
Date Published05/2017

Gravity wave forcing near the mesopause drives a summer‐to‐winter residual circulation in the mesosphere and a reversed, lower thermospheric winter‐to‐summer residual circulation. We conducted modeling studies to investigate how this lower thermospheric residual circulation impacts thermospheric composition (O/N2). We found that the upwelling associated with the residual circulation significantly decreases O/N2 in winter and the downwelling in summer slightly increases O/N2. Consequently, the residual circulation reduces the summer‐to‐winter latitudinal gradient of O/N2, which causes the simulated latitudinal gradient of O/N2 to be more consistent with observations. The smaller summer‐to‐winter latitudinal gradient of O/N2 would decrease the ionosphere winter anomaly in model simulations, which would bring the simulated winter anomaly into better agreement with ionospheric observations. The lower thermospheric residual circulation may be a process that has been largely ignored but is very important to the summer‐to‐winter latitudinal gradients, as well as annual/semiannual variations in the thermosphere and ionosphere.

Short TitleGeophys. Res. Lett.

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