Global Expansion of Tropical Cyclone Precipitation Footprint

Abstract

Precipitation from tropical cyclones (TCs) can cause massive damage from inland floods and will become more intense under warming climate. Knowledge gaps still exist in how the impact area and spatial pattern of heavy precipitation change with climate and environment. Here we defined a novel metric (DIST30) that represents the footprint of heavy TC precipitation based a high-resolution satellite precipitation product and global TC record over the past 41 years. We show that the DIST30 has increased significantly globally at a rate of 0.34 km per year. Spatially, DIST30 increases by 59.87% of the total TC impact area (8.79×107 km2), especially in the Western North Pacific, Northern Atlantic, and Southern Pacific. Machine learning model (XGBoost) demonstrated strong ability in both prediction performance and interpretation of the DIST30. We found that the monthly DIST30 variabilities are majorly controlled by the variations of TC maximum wind speed, TC location, sea surface temperature, vertical wind shear, and total water column. In particular, the DIST30 shows a very strong positive relationship with vertical wind shear. And more frequent TCs migrating to higher latitudes in North Hemisphere is the major contributor to the recent global upward trend in the DIST30.