Nighttime meridional neutral wind responses to SAPS simulated by the TIEGCM:A universal time effect  

作　　者：KeDeng Zhang Hui Wang WenBin Wang Jing Liu ShunRong Zhang Cheng Sheng 

机构地区：[1]Department of Space Physics,School of Electronic Information,Wuhan University,Wuhan 430072,China [2]High Altitude Observatory,National Center for Atmospheric Research,Boulder 80301,Colorado,USA [3]Haystack Observatory,Massachusetts Institute of Technology,Westford 01886,Massachusetts,USA [4]Department of Physics,University of Texas at Arlington,Arlington 76013,Texas,USA

出　　处：《Earth and Planetary Physics》2021年第1期52-62,共11页地球与行星物理（英文版）

基　　金：the National Science Foundation.The work is supported by the National Nature Science Foundation of China(No.s 41974182,41674153,41521063,41431073,41521062 and 42004135);the US NSF award AGS-1762141 and the US AFOSR MURI award FA9559-16-1-0364;the NSF grant AGS-1452309;The Spark Project at Wuhan University(2042020gf0024)also sponsors this work.

摘　　要：The present work uses the Thermosphere Ionosphere Electrodynamics General Circulation Model(TIEGCM),under geomagnetically disturbed conditions that are closely related to the southward interplanetary magnetic field(IMF),to investigate how the nighttime poleward wind(30°–50°magnetic latitude and 19–22 magnetic local time)responds to subauroral polarization streams(SAPS)that commence at different universal times(UTs).The SAPS effects on the poleward winds show a remarkable UT variation,with weaker magnitudes at 00 and 12 UT than at 06 and 18 UT.The strongest poleward wind emerges when SAPS commence at 06 UT,and the weakest poleward wind develops when SAPS occur at 00 UT.A diagnostic analysis of model results shows that the pressure gradient is more prominent for the developing of the poleward wind at 00 and 12 UT.Meanwhile,the effect of ion drag is important in the modulation of the poleward wind velocity at 06 and 18 UT.This is caused by the misalignment of the geomagnetic and geographic coordinate systems,resulting in a large component of ion drag in the geographically northward(southward)direction due to channel orientation of the SAPS at 06 and 18 UT(00 and 12 UT).The Coriolis force effect induced by westward winds maximizes(minimizes)when SAPS commence at 12 UT(00 UT).The centrifugal force due to the accelerated westward winds shows similar UT variations as the Coriolis force,but with an opposite effect.

关 键 词：Subauroral Polarization Streams TIEGCM poleward winds Universal time change 

分 类 号：P35[天文地球—空间物理学] P421.34[天文地球—地球物理学]