[P-EM06] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

★ [PEM06-12] Deep ionospheric hole created by sudden stratospheric warming in the post-midnight ionosphere

*Larisa GONCHARENKO¹、Anthea COSTER¹、Shunrong ZHANG¹、Phillip ERICKSON¹、Nestor APONTE² (1.Massachusetts Institute of Technology, Haystack Observatory、2.Arecibo Observatory, SRI International)

キーワード：sudden stratospheric warming, atmospheric coupling, ionosphere

Multiple observational studies have demonstrated large ionospheric variations associated with sudden stratospheric warming (SSW) events during the daytime, but only limited evidence of ionospheric disturbances during the night-time was reported up to now. We use observations by GPS TEC receivers and Arecibo and Millstone Hill incoherent scatter radars to investigate large-scale disturbances in the nighttime ionosphere for several SSW events. We report a deep decrease in TEC that reaches ~70% of the background level and is observed between the local midnight and local sunrise (6-12UT). This decrease is observed for several consecutive days in the range of latitudes from ~60oS to ~45oN. It is accompanied by a strong downward plasma motion and significant decrease in ion temperature, as observed by both Arecibo and Millstone Hill radars. We discuss variations in electric field and F-region dynamics as possible drivers of this behavior.