Mesospheric Short‐Period Gravity Waves in the Antarctic Peninsula Observed in All‐Sky Airglow Images and Their Possible Source Locations
Mesospheric Short‐Period Gravity Waves in the Antarctic Peninsula Observed in All‐Sky Airglow Images and Their Possible Source Locations
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DOI：
10.1029/2021jd035842
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发表时间：
2021-12
期刊：
影响因子：
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通讯作者：
H. Kam;In‐Sun Song;Jeong‐han Kim;Y. Kim;Byeong‐Gwon Song;Takuji Nakamura;Y. Tomikawa;Masaru Kogure;M. Ejiri;S. Perwitasari;M. Tsutsumi;Y. Kwak
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作者：
H. Kam;In‐Sun Song;Jeong‐han Kim;Y. Kim;Byeong‐Gwon Song;Takuji Nakamura;Y. Tomikawa;Masaru Kogure;M. Ejiri;S. Perwitasari;M. Tsutsumi;Y. Kwak
这项研究分析了2012-2016年期间在南极世宗国王站（KSS）的全天空相机（ASC）观测到的OH气辉图像。短周期重力波（<1 hr）的二维功率谱作为相速度的函数，使用采用ASC图像的时间序列的M变换方法获得。功率谱密度的振幅表明，中层波动活动在冬季（5月、6月和7月）最大，秋季（2月、3月和4月）最小。风阻图是在与二维谱相同的二维区域上使用MERRA-2再分析获得的z = 0-80 km水平风和KSS流星雷达数据获得的z = 80-90 km水平风绘制的。在气候上，缓慢传播的重力波（<30 m s−1）的谱区被风阻区覆盖，这表明平流层上部以下的风过滤了相位速度较小的重力波。冬季向东传播的重力波和春季（10月）强烈的东南向重力波未被平流层风过滤。谱分析还发现，这些未经滤波的重力波可能起源于平流层上部或中层下部，而不是对流层，这表明ASC观测平流层顶附近产生的次级重力波的可能性。
This study presents an analysis of OH airglow images observed from an all‐sky camera (ASC) at King Sejong Station (KSS), Antarctic for the 2012–2016 period. The two‐dimensional power spectra of short‐period gravity waves (<1 hr) as a function of phase velocities are obtained using the M‐transform method that employs the time sequence of ASC images. The amplitudes of the power spectral densities show that the mesospheric wave activity is the largest during winter (May, June, and July) and is the smallest in fall (February, March, and April). Wind‐blocking diagrams are constructed on the same two‐dimensional domain as in the two‐dimensional spectra using horizontal winds obtained from MERRA‐2 reanalysis at z = 0–80 km and from KSS meteor radar data at z = 80–90 km. Climatologically, the spectral regions of slowly propagating gravity waves (<30 m s−1) are overlaid by the wind‐blocking areas, which suggests the filtering of gravity waves with small phase speeds by winds below the upper stratosphere. Eastward propagating gravity waves in winter and intense south‐eastward waves in spring (October) are found to be unfiltered by the stratospheric winds. It is also found from the spectral analysis that these unfiltered gravity waves can originate from the upper stratosphere or the lower mesosphere, and not from the troposphere, which suggests the possibility of ASC observation of the secondary gravity waves generated near the stratopause.