Improved Climatology of Tropical Cyclone Precipitation from Satellite Passive Microwave Measurements

An accurate precipitation climatology is presented for tropical depression (TD), tropical storm (TS), and tropical cyclone (TC) occurrences over oceans using recently released, consistent, and high-quality precipitation datasets from all passive microwave sensors covering 1998-2012 along with the Automated Rotational Center Hurricane Eye Retrieval (ARCHER)-based TC center positions. Impacts with respect to the direction of both TC movement and the 200-850-hPa wind shear on the spatial distributions of TC precipitation are analyzed. The TC eyewall contraction process during its intensification is noted by a decrease in the radius of maximum rain rate with an increase in TC intensity. For global TCs, the maximum rain rate with respect to the direction of TC movement is located in the down-motion quadrants for TD, TS, and category-1-3 TCs, and in a concentric pattern for category-4/5 TCs. A consistent maximum TC precipitation with respect to the direction of the 200-850-hPa wind shear is shown in the downshear left quadrant (DSLQ). With respect to direction of TC movement, spatial patterns of TC precipitation vary with basins and show different features for weak and strong storms. The maximum rain rate is always located in DSLQ for all TC categories and basins, except the Southern Hemisphere basin where it is in the downshear right quadrant. This study not only confirms previously published results on TC precipitation distributions relative to vertical wind shear direction, but also provides a detailed distribution for each TC category and TS, while TD storms display an enhanced rainfall rate ahead of the downshear quadrants.

Automated summary

This study presents an accurate precipitation climatology for tropical depression (TD), tropical storm (TS), and tropical cyclone (TC) occurrences over oceans using high-quality precipitation datasets and TC center positions. The study analyzes the impacts of TC movement direction and wind shear on the spatial distribution of TC precipitation, as well as the eyewall contraction process during TC intensification. The research confirms previously published results on TC precipitation distributions in relation to wind shear direction and provides detailed distributions for each TC category and TS.