A long-term perspective of hydroclimatological impacts of tropical cyclones on regional heavy precipitation over eastern monsoon China

Combining a multitemporal clustering algorithm and an objective synoptic analysis technique, we develop an objective identification approach to identify tropical cyclone (TC)-induced regional heavy precipitation events (RHPEs) during 1961-2018 over eastern monsoon China (EMC) based on 0.25 degrees gridded precipitation dataset. Over the past 58 years, there are around 500 TC-induced RHPEs over the EMC, and the features (i.e. duration, impact area, precipitation depth, and total precipitation volume) of these events show obviously skewed distribution and strong seasonality. Seasonal variations in the features of TC-induced RHPEs show inverted V shapes and peak values in the inverted V shapes occur in July. More than 40% of RHPEs in coastal areas of southern China are triggered by TCs and this fractional contribution is also observed in northeastern China for RHPEs exceeding 50 mm/grid/day. Both frequency and duration of TC-induced RHPEs are significantly increasing in southeastern and northeastern China. Additionally, the EMC is experiencing more frequent, more widespread, and greater TC-induced RHPEs. There is also a signal of interdecadal variability in the features of TC-induced RHPEs. Anomalies of prevalent easterlies, westward steering flow, weakening vertical wind shear, and enhanced integrated vapor transport occur in years with severe TC-induced RHPEs. Meanwhile, the exceedance probability of extreme TC-induced RHPEs is increasing in recent decades, and this increase is more pronounced for destructive events (i.e. TC-induced RHPEs with long return intervals). This probability of extreme TC-induced RHPEs depends on TC activity characteristics, such as intensity and translation speed. Given that TCs tend to get stronger, decay slower, and linger longer in a warming climate, it is of great challenge for society to address the increasing risk of catastrophic disasters associated with extreme TC-induced RHPEs.

Automated summary

Based on the analysis of TC-induced RHPEs in eastern monsoon China, it was found that the frequency and duration of these events have significantly increased over the past few decades, showing seasonal and interdecadal variability. With the warming climate, the exceedance probability of extreme TC-induced RHPEs, especially destructive ones, is on the rise, posing a great challenge to society in dealing with the increasing risk of catastrophic disasters associated with these events.