Wind Variations in the Mesosphere and Lower Thermosphere Near 60°S Latitude During the 2019 Antarctic Sudden Stratospheric Warming

Guiping Liu, Diego Janches, Ruth S. Lieberman, Tracy Moffat-Griffin, Nicholas J. Mitchell, Jeong Han Kim, Changsup Lee

Research output: Contribution to journalArticlepeer-review

Abstract

Sudden stratospheric warmings (SSWs) could act as an important mediator in the vertical coupling of atmospheric regions and dramatic variations in the mesosphere and lower thermosphere (MLT) in response to SSWs have been documented. However, due to rare occurrences, SSWs in the Southern Hemisphere (SH) and their impacts on the MLT dynamics are not well understood. This study presents an analysis of MLT winds at ∼80–98 km altitudes measured by meteor radars located at Tierra del Fuego (53.7°S, 67.7°W), King Edward Point (54.3°S, 36.5°W) and King Sejong Station (62.2°S, 58.8°W) near 60°S latitude during the Antarctic winter. Eastward zonal winds from these stations are observed to decrease significantly near the peak date of the 2019 Antarctic SSW, and both zonal and meridional winds in 2019 exhibit considerable differences to the mean winds averaged over other non-SSW years. A quasi 6-day oscillation is observed at all three radar locations, being consistent with the presence of the westward propagating zonal wave-1 planetary wave. The vertical wavelength of this wave is estimated to be ∼55 km, and the enhancement of the wave amplitude during this SSW is noticeable. Evidence of the interaction between the 6-day wave and the semidiurnal diurnal tide is provided, which suggests a possible mechanism for SSWs to impact the upper atmosphere. This study reports the large-scale variations in winds in the MLT region at SH midlatitudes to high latitudes in a key dynamic but largely unexplored latitudinal band in response to the 2019 Antarctic SSW.

Original languageEnglish
Article numbere2020JA028909
JournalJournal of Geophysical Research: Space Physics
Volume126
Issue number5
Early online date30 Apr 2021
DOIs
Publication statusPublished - 31 May 2021

Keywords

  • mesosphere and lower thermosphere
  • mesospheric wind
  • planetary wave
  • planetary wave-tide interaction
  • tides
  • upper atmosphere

ASJC Scopus subject areas

  • Space and Planetary Science
  • Geophysics

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