Abstract

The relationship of cirrus clouds and areas of increased relative humidity in the upper troposphere with symmetric instability developing on the subtropical (anticyclonic) side of jet streams are explored. Theoretical arguments are supplemented by case studies related to the Northern and Southern hemispheres. Using satellite images of cirrus clouds and reanalysis data, the values of the vertical eddy viscosity, which compensates for the inviscid growth of disturbances in case of symmetric instability, are estimated. At the levels of 250 and 200 hPa, a significant correlation between high relative humidity and potential vorticity characteristic of symmetric instability is confirmed.

中文翻译：

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卷云与对称不稳定对流层上层相对湿度场的关系

摘要

探讨了卷云与对流层上层相对湿度增加区域以及急流副热带（反气旋）侧发展的对称不稳定性的关系。与北半球和南半球相关的案例研究补充了理论论证。使用卷云的卫星图像和再分析数据，估计了垂直涡粘性的值，该值补偿了对称不稳定情况下扰动的无粘性增长。在250和200 hPa水平上，高相对湿度与对称不稳定位涡特征之间存在显着相关性。