JpGU-AGU Joint Meeting 2020

講演情報

[E] 口頭発表

セッション記号 P (宇宙惑星科学) » P-EM 太陽地球系科学・宇宙電磁気学・宇宙環境

[P-EM12] 大気圏ー電離圏結合

コンビーナ:Huixin Liu(九州大学理学研究院地球惑星科学専攻 九州大学宙空環境研究センター)、大塚 雄一(名古屋大学宇宙地球環境研究所)、Yue Deng(University of Texas at Arlington)、Loren Chang(Institute of Space Science, National Central University)

[PEM12-23] Recurrent high-speed solar wind co-rotating interaction region imprint on the ionosphere and atmosphere: GPS TEC variations and atmospheric gravity waves

*Paul Prikryl1,2James M. Weygand3Reza Ghoddousi-Fard4Lidia Nikitina2Bharat S. R. Kunduri5 (1.Physics Department University of New Brunswick, Canada 、2.Geomagnetic Laboratory Natural Resources Canada、3.Earth Planetary and Space Sciences, University of California, USA、4.Canadian Geodetic Survey Natural Resources Canada 、5.Bradley Dept. of Electrical and Computer Engineering, Virginia Tech, USA)

キーワード:Polar and auroral ionosphere, High-speed solar wind stream, Solar wind-magnetosphere-ionosphere-atmosphere coupling, Atmospheric gravity wave, Extratropical and tropical cyclones

High-speed streams (HSS) from coronal holes dominate solar wind structure in the absence of coronal mass ejections during solar minimum and the descending branch of solar cycle. Prominent and long-lasting coronal holes produce intense co-rotating interaction regions (CIR) on the leading edge of high-speed plasma streams that cause recurrent ionospheric disturbances and geomagnetic storms. Through solar wind coupling to the magnetosphere-ionosphere-atmosphere (MIA) system they affect the ionosphere and neutral atmosphere at high latitudes, and, at mid to low latitudes, by the transmission of the electric fields [1] and propagation of atmospheric gravity waves from the high-latitude lower thermosphere [2].
The high-latitude ionospheric structure, caused by precipitation of energetic particles, strong ionospheric currents and convection, results in changes of the GPS total electron content (TEC) and rapid variations of GPS signal amplitude and phase, called scintillation [3]. The GPS phase scintillation is observed in the ionospheric cusp, polar cap and auroral zone, and is particularly intense during geomagnetic storms, substorms and auroral breakups. Phase scintillation index is computed for a sampling rate of 50 Hz by specialized GPS scintillation receivers from the Canadian High Arctic Ionospheric Network (CHAIN). A proxy index of phase variation is obtained from dual frequency measurements of geodetic-quality GPS receivers sampling at 1 Hz, which include globally distributed receivers of the RT-IGS network that are monitored by the Canadian Geodetic Survey in near-real-time [4]. Temporal and spatial changes of TEC and phase variations following the arrivals of HSS/CIRs [5] are investigated in the context of ionospheric convection and equivalent ionospheric currents derived from the ground magnetometer network using the spherical elementary current system method [6,7].
The Joule heating and Lorentz forcing in the high-latitude lower thermosphere have long been recognized as sources of internal atmospheric gravity waves (AGWs) [2] that propagate both upward and downward, thus providing vertical coupling between atmospheric layers. In the ionosphere, they are observed as traveling ionospheric disturbances (TIDs) using various techniques, e.g., de-trended GPS TEC maps [8].
In this paper we examine the influence on the Earth’s ionosphere and atmosphere of a long-lasting HSS/CIRs from recurrent coronal holes at the end of solar cycles 23 and 24. The solar wind MIA coupling, as represented by the coupling function [9], was strongly increased during the arrivals of these HSS/CIRs.

[1] Kikuchi, T. and K. K. Hashimoto, Geosci. Lett. , 3:4, 2016.
[2] Hocke, K. and K. Schlegel, Ann. Geophys., 14, 917–940, 1996.
[3] Prikryl, P., et al., J. Geophys. Res. Space Physics, 121, 10448–10465, 2016.
[4] Ghoddousi-Fard et al., Advances in Space Research, 52(8), 1397-1405, 2013.
[5] Prikryl et al. Earth, Planets and Space, 66:62, 2014.
[6] Amm O., and A. Viljanen, Earth Planets Space, 51, 431–440, 1999.
[7] Weygand J.M., et al., J. Geophys. Res., 116, A03305, 2011.
[8] Tsugawa T., et al., Geophys. Res. Lett., 34, L22101, 2007.
[9] Newell P. T., et al., J. Geophys. Res., 112, A01206, 2007.