Polar vortex strength impacts on the longitudinal structure of thermospheric composition and ionospheric electron density | CU Experts

This work examines the weak stratospheric polar vortex (SPV) event of; February 2008 and the strong SPV event of February 2021 to understand; the potential influence of SPV strength on midlatitude thermospheric; composition and ionospheric plasma density. The weak SPV event shows a; reduction in thermospheric O/N2 at all longitudes, changes in the; ionospheric total electron content (TEC) that vary with longitude, and; an intensification of the semidiurnal tides. The strong SPV event shows; O/N2 elevated by up to 25% in the Asian sector and a 25% decrease in; semidiurnal tidal amplitude. The TEC response during the strong SPV; event is complex, but shows enhanced TEC in the Asian sector where O/N2; is elevated. These are the first observations of anomalies in the; thermospheric composition and ionospheric plasma associated with a; strong polar vortex event.

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