How different is tropical cyclone precipitation over land and ocean?

Abstract

Tropical cyclone (TC) precipitation is a major cause of severe floods and landslides. This study compares the characteristics of TC precipitation over land and ocean in the Northern Hemisphere using satellite data from 2001 – 2020. An analog selection method is used to pair each landfalling TC case with an oceanic case of the same intensity and similar atmospheric environmental conditions. Here we show robust discrepancies in rainfall rate and pattern for TCs over land and ocean. The average rain rates of landfalling TCs are 27.8% lower than those of oceanic TCs. Nonetheless, the rainfall is more intense on the right side of landfalling TCs compared with oceanic TCs. This left-right difference pattern tends to be more pronounced for TCs with faster translation speeds. Numerical simulations indicate that the increased surface friction and moisture convergence are largely responsible for the increased rainfall rate on the right side of landfalling TCs.