A numerical investigation on the formation of the stalling of the cross-polar jet in midnight thermospheric winds

Recent observations from the Scanning Doppler Imager at Poker Flat indicated a distinct feature that the cross-polar jet stalls over short horizontal distances around the magnetic midnight. However, the mechanisms responsible for the occurrence of stalling have not been well understood.

In this study, we investigated the physical mechanisms of the stalling of the cross-polar jet based on the Thermosphere Ionosphere Electrodynamics General Circulation Model simulations. The model reproduced the general stalling features at midnight over a short horizontal distance. The occurrence of stalling is mainly associated with Joule heating, which enhances the neutral temperature and then turns winds poleward by the pressure gradient force, and ion-neutral coupling, which drags neutral winds westward in the pre magnetic local time midnight sector and contributes to the poleward turning of the meridional winds by the poleward Coriolis force.