JpGU-AGU Joint Meeting 2020

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[E] Oral

P (Space and Planetary Sciences ) » P-EM Solar-Terrestrial Sciences, Space Electromagnetism & Space Environment

[P-EM20] Recent Advances in Ionosphere Observation and Modeling through New Observation Opportunities

convener:CHIYEN LIN(Center for Astronautical Physics and Engineering, National Central University, TAIWAN), Yen-Jung Wu(Space Sciences Laboratory, University of California, Berkeley), Yang-Yi Sun(China University of Geosciences), Charles Lin(Department of Earth Sciences, National Cheng Kung University)

[PEM20-01] Ionospheric Variability during the September 2019 Southern Hemisphere Sudden Stratospheric Warming

★Invited Papers

*Yosuke Yamazaki1, Vivien Matthias2, Yasunobu Miyoshi3, Claudia Stolle1,4, Tarique Siddiqui1, Guram Kervalishvili1, Jan Laštovička5, Michal Kozubek5, William Ward6, David Themens6, Samuel Kristoffersen6, Patrick Alken7,8 (1.GFZ Potsdam, 2.PIK Potsdam, 3.Kyushu Univ., 4.Univ. of Potsdam, 5.CAS Prague, 6.Univ. of New Brunswick, 7.Colorado Univ., 8.NOAA)

Keywords:sudden stratospheric warming, quasi-6-day wave, Swarm

A sudden stratospheric warming (SSW) is an extreme wintertime meteorological phenomenon occurring mostly over the Arctic region. Studies have shown that an Arctic SSW can influence the whole atmosphere including the ionosphere. In September 2019, a rare SSW event occurred in the Antarctic region, following strong wave-1 planetary wave activity (see attached figure). The event provides an opportunity to investigate its broader impact on the upper atmosphere, which has been largely unexplored in previous studies. Ionospheric data from ESA's Swarm satellite constellation mission show prominent 6-day variations in the dayside low-latitude region during the SSW, including 20-70% variations in the equatorial zonal electric field, 20-40% variations in the electron density, and 5-10% variations in the top-side total electron content. These ionospheric variations have characteristics of a westward-propagating wave with zonal wavenumber 1, and can be attributed to forcing from the middle atmosphere by the Rossby normal mode “quasi-6-day wave” (Q6DW). Geopotential height measurements by the Microwave Limb Sounder aboard NASA's Aura satellite reveal a burst of global Q6DW activity in the mesosphere and lower thermosphere at this time, which is one of the strongest in the record. These results suggest that an Antarctic SSW can lead to ionospheric variability by altering middle atmosphere dynamics and propagation characteristics of large-scale waves from the middle atmosphere to the upper atmosphere.