Investigating Changes in Tropical Cyclone Inner Core and Outer Rainband Precipitation in Models under Warming Scenarios

Abstract

Extreme precipitation from tropical cyclones (TCs) commonly results in fatalities and expensive property damage in both coastal locations and hundreds of miles inland. Recent studies have found a decreasing trend in TC inner core precipitation and an increasing trend in outer rainband precipitation using about 20 years of precipitation data from satellite products. Most modeling studies that have looked at the response of TC precipitation to climate change found either an increase in the inner core only or an increase in both the inner core and outer rainbands; however, the models were too coarse to resolve detailed TC precipitation structures. This work uses high-resolution Weather Research and Forecasting (WRF) simulations to explore how three-dimensional TC convective structures and precipitation respond to both idealized and more realistic warming scenarios. TCs in the idealized simulations show increasing precipitation in both the TC inner core and outer rainbands with warmer SST, in disagreement with the decrease in inner core precipitation over time in observations. This suggests that either these model simulations are too idealized to simulate the observed decrease in inner core precipitation or the models are missing a key physical process happening in real-world TCs. It also suggests that the disagreements between TC precipitation trends with warming in models and satellite observations are not caused by insufficient model resolution. Results from these idealized simulations will be compared to TCs in 20-year-long historical and future climate runs in regional WRF.