Wind Variations in the Mesosphere and Lower Thermosphere Near 60°S Latitude During the 2019 Antarctic Sudden Stratospheric Warming
Wind Variations in the Mesosphere and Lower Thermosphere Near 60°S Latitude During the 2019 Antarctic Sudden Stratospheric Warming
复制标题
DOI：
10.1029/2020ja028909
复制
发表时间：
2021-04
期刊：
影响因子：
--
通讯作者：
Guiping Liu;D. Janches;R. Lieberman;T. Moffat‐Griffin;N. Mitchell;Jeong‐han Kim;Changsup Lee
中科院分区：
文献类型：
--
作者：
Guiping Liu;D. Janches;R. Lieberman;T. Moffat‐Griffin;N. Mitchell;Jeong‐han Kim;Changsup Lee
平流层突然变暖（SSWs）可以作为大气区域垂直耦合的重要介质，并在中层和低热层（MLT）响应SSWs的剧烈变化已被证实。然而，由于罕见的发生，SSW在南半球（SH）和它们的影响MLT动力学还没有得到很好的理解。本研究分析了南极冬季期间位于火地岛（53.7°S，67.7°W），爱德华国王角（54.3°S，36.5°W）和世宗国王站（62.2°S，58.8°W）附近60°S纬度的流星雷达测量的80-98 km高度的MLT风。据观察，这些站的向东纬向风在2019年南极SSW的峰值日期附近显着减少，2019年的纬向风和纬向风与其他非SSW年份的平均风存在相当大的差异。在所有三个雷达位置都观测到准6天振荡，这与向西传播的纬向波-1行星波的存在相一致。这波的垂直波长估计为1055公里，在这SSW波振幅的增强是明显的。提供了6日波和半日潮相互作用的证据，这表明SSW影响高层大气的可能机制。这项研究报告了在SH中纬度到高纬度的MLT地区风的大规模变化，这是一个关键的动态，但在很大程度上尚未探索的纬度带，以响应2019年南极SSW。
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.