Effects of Subauroral Polarization Streams on the Upper Thermospheric Winds During Non‐Storm Time
Name
JGR Space Physics - 2022 - Zou - Effects of Subauroral Polarization Streams on the Upper Thermospheric Winds During.pdf
Description
Published version
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2.83 MB
Format
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Checksum (MD5)
3009defbde453f6ef52190e674d264e8
Author(s)
Zou, Ying
Lyons, Larry R
Shi, Xueling
Liu, Jiang
Wu, Qian
Conde, Mark
Shepherd, Simon G
Mende, Stephen
Zhang, Yongliang
Coster, Antea
Date Issued
April 11, 2022
Journal
Journal of Geophysical Research: Space Physics
Publisher
American Geophysical Union
Citation
Zou, Y., Lyons, L. R., Shi, X., Liu, J., Wu, Q., Conde, M., et al. (2022). Effects of subauroral polarization streams on the upper thermospheric winds during non-storm time. Journal of Geophysical Research: Space Physics, 127, e2021JA029988.
Version
Final published version
Abstract
Intense sunward (westward) plasma flows, named Subauroral Polarization Stream (SAPS), have been known to occur equatorward of the electron auroras for decades, yet their effect on the upper thermosphere has not been well understood. On the one hand, the large velocity of SAPS results in large momentum exchange upon each ion-neutral collision. On the other hand, the low plasma density associated with SAPS implies a low ion-neutral collision frequency. We investigate the SAPS effect during non-storm time by utilizing a Scanning Doppler Imager (SDI) for monitoring the upper thermosphere, SuperDARN radars for SAPS, all-sky imagers and DMSP Spectrographic Imager for the auroral oval, and GPS receivers for the total electron content. Our observations suggest that SAPS at times drives substantial (>50 m/s) westward winds at subauroral latitudes in the dusk-midnight sector, but not always. The occurrence of the westward winds varies with AE index, plasma content in the trough, and local time. The latitudinally averaged wind speed varies from 60 to 160 m/s, and is statistically 21% of the plasma. These westward winds also shift to lower latitude with increasing AE and increasing MLT. We do not observe SAPS driving poleward wind surges, neutral temperature enhancements, or acoustic-gravity waves, likely due to the somewhat weak forcing of SAPS during the non-storm time.
MIT Department
Haystack Observatory
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DOI of Published Version
https://doi.org/10.1029/2021JA029988
