JpGU-AGU Joint Meeting 2017

Presentation information

[EE] Oral

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

[P-EM11] [EE] Mesosphere-Thermosphere-Ionosphere Coupling in the Earth's Atmosphere

Wed. May 24, 2017 10:45 AM - 12:15 PM A01 (Tokyo Bay Makuhari Hall)

convener:Loren Chang(Institute of Space Science, National Central University), Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University), Akinori Saito(Department of Geophysics, Graduate School of Science, Kyoto University), Tzu-Wei Fang, Chairperson:Huixin Liu(Earth and Planetary Science Division, Kyushu University SERC, Kyushu University)

12:00 PM - 12:15 PM

[PEM11-15] Impact of Midnight Thermosphere Dynamics on the Nighttime Middle- and Low-latitude Ionosphere

*Tzu-Wei Fang1, Rashid Akmaev2, YenChieh Lin3, Russell Stoneback4, Tim Fuller-Rowell1 (1.University of Colorado Boulder, USA, 2.NOAA Space Weather Prediction Center, USA, 3.National Central University, Taiwan, 4.University of Texas at Dallas, USA)

Keywords:Midnight Temperature Maximum, Low-latitude ionosphere, Equatorial Vertical Drift

Simulations using the coupled Whole Atmosphere Model and Global Ionosphere Plasmasphere Model (WAM/GIP) have successfully reproduced the unusual upward drift during the post-midnight period (~2-3 LT) that were observed by C/NOFS satellite during the recent solar minimum. Model produces significant day-to-day variability in the nighttime equatorial ionosphere and also reveals strong seasonal and longitudinal dependence of the nighttime upward drift. Our analysis indicates that the upward drifts are driven by thermosphere dynamics associated with the midnight temperature maximum (MTM). The MTM locally reverses the typical large-scale zonal and meridional wind pattern, in turn affecting the nighttime F-layer electrodynamics. The longitudinal variation of the drifts depends on the magnitude and position of the MTM peak relative to the magnetic equator. In this talk, we will present the morphology and characteristics of the post-midnight upward drift shown in the simulations and explain its causal mechanism. Additionally, simulation of growth rate of Rayleigh–Taylor instability associated with the nighttime upward drift and brightness waves produced by the MTM will also be discussed.