Analysis of characteristics of heavy rainfall events induced by landfalling tropical cyclones in China from 1980 to 2020

Abstract

[Objective] China is one of the countries most severely affected by heavy rainfall from tropical cyclones,incurring annual economic losses amounting to hundreds of billions of yuan.Understanding the variation characteristics of these events is crucial for flood prevention and disaster mitigation efforts. [Methods] Based on hourly rainfall data from 1 185 meteorological stations in China and the best track dataset of tropical cyclones,heavy rainfall events were defined using an absolute threshold method.Linear regression was employed to analyze the characteristics of hourly-scale heavy rainfall events induced by landfalling tropical cyclones in China from 1980 to 2020.The analysis focused on the spatiotemporal distribution of these events and the interannual variation trends in frequency,intensity,and duration of events with different durations (short-duration:1~6 h,medium-duration:7~12 h,and long-duration:>12 h). [Results] (1) Heavy rainfall events induced by landfalling tropical cyclones mainly occurred in Hainan Island and the southeastern coastal areas of China,with their intensity weakening toward inland and northern areas.The overall intensity of such events showed an increasing trend.The duration of heavy rainfall events tended to decrease from south to north and from coastal to inland areas,with Hainan exhibiting the longest duration (6.22 h/a).Areas with increasing trends in event frequency,intensity,and duration were mainly located along the southern coast,the lower reaches of the Yangtze River,and Shandong Province.(2) In rainfall events induced by landfalling tropical cyclones with different durations,long-duration events accounted for the highest proportion (39.75%) and showed an increasing trend in frequency along with short-duration events.The rainfall intensity of both types was increasing,but the duration of long-duration events continued to rise,while that of short-and medium-duration events was decreasing. [Conclusion] From 1980 to 2020,the intensity of heavy rainfall events induced by landfalling tropical cyclones has increased,and event durations have been prolonged,exerting profound impacts on the socioeconomic development and ecological security in some regions of China.The increasing frequency,intensity,and duration of long-duration heavy rainfall events pose significant challenges for disaster prevention in both coastal and inland areas of the country.

Keywords

landfalling tropical cyclone / rainfall event / spatiotemporal distribution / temporal trend / duration / precipitation intensity / influencing factors

Funding

General Program of National Natural Science Foundation of China(42271081)

General Program of National Natural Science Foundation of China(42071024)

Innovation and Development Project of the China Meteorological Administration(CXFZ2024J037)