The Stratosphere-Ionosphere-Protonosphere Coupling: Evidence From the Ion Composition Observations During the 2009 Sudden Stratospheric Warming

Previous studies suggested that sudden stratospheric warmings (SSW) change the global atmosphere from troposphere to thermosphere/ionosphere. We report the low-latitude O+ and H+ composition at 840-km altitude during the 2009 SSW, with the DMSP satellite morning measurements. Our results indicate that the stratospheric variation around 30-km altitude modulates the ion exchange between the ionosphere and protonosphere via the vertical and field-aligned plasma drifts due to the enhanced lunar semidiurnal tides. The upward disturbance drift uplifts the ionospheric O+ into the protonosphere, and most O+ is changed to H+ via chemical coupling, while the O+/H+ transition height does not change under combined effects of the southward and upward disturbance drifts on 24-29 January. The disturbance drift turns downward, lowers the O+/H+ transition height, depletes the O+ density in the protonosphere, and the H+ at higher altitudes moves downward to supply the H+ at 840 km from 30 January to 5 February.