日本东京大学Kaoru Sato的研究组在南极利用PANSY雷达探测到对流层和平流层下部的开尔文-亥姆霍兹波浪。2023年2月21日出版的《JGR大气》发表了这项成果。

课题组表示，研究区共探测到73个开尔文-亥姆霍兹(K-H)巨浪，并详细分析了两个可能由同一气旋激发典型案例。在第一种情况下，开尔文-亥姆霍兹巨浪的厚度约为800 m，水平波长约为2500 m，观测时间最长约为6.5 h。根据数值模拟，与气旋相关的持续存在的重力波足以引发开尔文-亥姆霍兹不稳定的强垂直风切变。在第二种情况下，开尔文-亥姆霍兹巨浪的水平波长约为4320 m，最深厚度约为1600 m。

数值模拟表明，增强的对流层高空急流与发展良好的天气尺度气旋共同引导了开尔文-亥姆霍兹不稳定。这种背景条件经常在南极沿海地区观测到，是开尔文-亥姆霍兹激发的典型机制。线性稳定性分析还表明，观测到的开尔文-亥姆霍兹波浪的特征与最不稳定模式一致。对73例观察病例的主题资料进行统计分析。在昭和站观测到的开尔文-亥姆霍兹波浪特征与在日本观测到的相似。然而，开尔文-亥姆霍兹巨浪在昭和站的波浪周期往往比在日本长，可能是由于南极对流层射流较弱的缘故。

据悉，2019年，研究组在南极昭和站项目中针对对流层和平流层低层湍流，采用频域雷达干涉成像技术，使用雷达(PANSY)和无线电探空仪进行了两次10天的观测活动，并在南极昭和站获得探空观测数据。

附：英文原文

Title: Kelvin-Helmholtz Billows in the Troposphere and Lower Stratosphere Detected by the PANSY Radar at Syowa station in the Antarctic

Author: Yuichi Minamihara, Kaoru Sato, Masaki Tsutsumi

Issue&Volume: 2023-02-21

Abstract: We conducted two 10-day observational campaigns in 2019 targeting turbulence in the troposphere and lower stratosphere by adopting a frequency domain radar interferometric imaging technique using Program of the Antarctic Syowa (PANSY) radar and radiosonde observations obtained at Syowa Station in the Antarctic. 73 Kelvin-Helmholtz (K-H) billows were detected, and two characteristic cases likely excited by the same cyclone were examined in detail. In the first case with the longest observational duration of ～6.5 h, the K-H billows had a thickness of ～800 m and a horizontal wavelength of ～2500 m. According to a numerical simulation, continuously existing gravity waves associated with the cyclone maintained strong vertical wind shear sufficient to cause the K-H instability. In the second case with the deepest thickness of ～1600 m, the K-H billows had a horizontal wavelength of ～4320 m. Numerical simulation suggested that an enhanced upper-tropospheric jet associated with a well-developed synoptic-scale cyclone caused the K-H instability. Such background conditions, frequently observed in the Antarctic coastal region, are typical mechanisms for K-H excitation. Linear stability analysis also indicated that the characteristics of the observed K-H billows were consistent with the most unstable modes. Furthermore, statistical analysis was performed using data of all 73 observed cases. The characteristics of K-H billows observed at Syowa Station are similar to those observed over Japan. However, the K-H billows tend to have longer wave periods over Syowa Station than over Japan, likely due to the weaker tropospheric jet in the Antarctic.

DOI: 10.1029/2022JD036866

Source:https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2022JD036866