Compound temporal-spatial extreme precipitation events in the Poyang Lake Basin of China

Study region: The study region is the Poyang Lake Basin (PLB). As a typical humid subtropical basin in China, the PLB is crisscrossed by rivers and lakes, where frequent hydrological and meteorological processes occur. Study focus: This study identified temporal extreme precipitation, spatial extreme precipitation, and compound temporal-spatial extreme precipitation events to investigate precipitation extremes. The differences in occurrence of compound widespread-persistent extreme precipitation (WPEP), persistent extreme precipitation (PEP) and widespread extreme precipitation (WEP) events were investigated using the Weather Research and Forecast (WRF) model. New hydrological insights for the region: Extreme precipitation events characterized by high intensity and long duration were more likely to occur in the northern part of the PLB. The frequency of extreme precipitation showed an increasing trend in the central and northeastern regions of the PLB. The contribution of PEP increased from an average of 30.7 % during the period 1983–1992 to 37.2 % during 2013–2022. The WPEP event exhibited a prolonged duration, greater precipitation intensity, and higher precipitable water (PW) and water vapor mixing ratio at 2 m (Q2). Significant changes in PW and Q2 were observed prior to the occurrence of the PEP event. However, PW and Q2 values remained stable during WEP and WPEP events. The PLB was influenced by two water vapor sources, from the north and southwest during the WEP and WPEP events.