Abstract

China is significantly impacted by torrential rainfall induced by tropical cyclone (TC) activity particularly in South China (SC) and East China (EC). This study delineates the distinct TC activities associated with these regions over the western North Pacific (WNP). Our analysis reveals that in SC, positive TC rainfall is largely attributed to a significant increase in TC genesis within the South China Sea (SCS), along with predominantly westward TC tracks. In EC, rainfall patterns are influenced by a northward extension of both TC genesis and tracks, notably affecting areas such as the Yangtze River delta and Shandong Province. This study further explores the modulation effects of preceding sea surface temperature (SST) anomalies in the eastern Indian Ocean (EIO) and the eastern Pacific on summer TC rainfall in SC and EC. We find that autumn warming in the EIO enhances subsequent summer TC rainfall in SC by modulating cyclonic anomalies along with favorable conditions for TC genesis and convection over the SC coast, while simultaneously diminishing convections over EC. Meanwhile, La Niña events lead to increased TC rainfall in EC during the subsequent summer by modifying the large-scale background circulation. This modification promotes TC formation at higher latitudes and facilitates more TCs moving northwestward directly toward EC. This research provides valuable insights into the distinct underlying mechanisms driving regional TC rainfall variation, highlighting the importance of region-specific analyses in understanding and forecasting TC impacts in China.