A global survey of stratospheric gravity waves generated by tropical cyclones

Abstract

The stratospheric gravity waves generated by tropical cyclones (TC-SGWs) are useful for the monitoring of tropical cyclones (TCs) and are also important for the gravity-wave parameterization in numerical models, as they represent a distinct type of gravity waves. Previous studies on TC-SGWs have not characterized TC-SGW global distribution and corresponding local structure related to the background wind. Here we show the global distribution of the TC-SGWs based on 21 years of Atmospheric Infrared Sounder observations, and reveal three global hotspots of the waves as the North Atlantic-Northeast Pacific, the Northwest Pacific, and the South Pacific-Southern Indian region. We also characterize the local structure of the three hotspots and find that although displaying diverse anisotropic structures, they are all shaped by the combination of filtering and refraction effects of the background wind. Our findings provide a guide for global TC-SGW hotspots and demonstrate the contributions of the background wind, which can further provide a preliminary guide for TC monitoring through satellite observations of TC-SGWs.