Revisiting the mechanisms for the observed decrease in inner-core tropical cyclone precipitation

Tropical cyclone precipitation (TCP) is expected to intensify under global warming, yet recent observations show a decline in annual inner-core TCP. Here, we revisit this observed trend and its underlying mechanisms. By incorporating multiple observational datasets, we find the decreasing trend is robust across different products. However, previous explanations fail to fully explain this trend. Using a simple TCP model, we demonstrate that the inner-core TCP decrease is primarily driven by a declining trend in annual mean maximum wind speed, accompanied by an increasing trend in the annual mean radius of maximum wind. A shift in TC intensity distribution, with more tropical storms and fewer Category 1–2 and Category 3–5 TCs, explains the reduction in annual mean maximum wind speed.