Linkages Between Tropical Cyclones and Extreme Precipitation over China and the Role of ENSO

Abstract

Abstract This research investigated the linkages between tropical cyclones (TCs) and extreme precipitation, and their associations with El Niño-Southern Oscillation (ENSO) over China. The contribution of TC-induced to total extreme precipitation events along the southeast coast of China was higher than 50%, and the values gradually decreased as TCs moved inland. However, the precipitation extremes (magnitude and frequency) related to TCs did not show statistically significant changes over the most recent 57 years. The impacts of TCs on precipitation extremes are evidently modulated by the ENSO phases. We found less extreme precipitation linked with TCs in southeastern China during El Niño phase, because of the fewer TC tracks over this region and less TC genesis in the western North Pacific (WNP). The small TC track density over southeastern China is due to the prevalent westerly steering flow and abnormal integrated vapor transport from northern to southern China during El Niño years. Additionally, warmer sea surface temperature, more vigorous westerlies, larger vorticity in 250 hPa, and higher divergence in 850 hPa in an El Niño phase jointly displaced the mean genesis of the WNP TCs eastward and this led to fewer TCs passing through southeastern China.