Long-term Variation Pattern of Heavy Precipitation Events in the Taihu Economic Circle under the Background of Climate Change

Abstract

This study focuses on three cities (Suzhou, Wuxi, and Changzhou) in the Taihu Economic Circle to explore the long-term variation characteristics of heavy precipitation events. Based on daily precipitation data from the National Aeronautics and Space Administration (NASA) Prediction of Worldwide Energy Resources (NASA POWER) database from 1982 to 2024, this study defines a heavy precipitation event as a day with precipitation exceeding 20 mm to analyze the variation further. Results show annual precipitation increased significantly. Specifically, June 2024 precipitation surged, while July-August saw abnormal drops in some cities. Linear regression reveals annual heavy precipitation frequency rises 1.6-1.9 days per decade, with other possible influencing factors to be considered, such as the combined effects of El Niño/ La Niña-Southern Oscillation (ENSO), global warming, and urbanization. This study reveals increased heavy precipitation risk, which can provide a basis for climate adaptation strategies. In the future, multivariate analysis will still be needed to further quantify the contributions of different influencing factors.