Persistent and nonpersistent regional extreme total, daytime, and night‐time precipitation events over southwest China (1961–2019)

Abstract

AbstractExtreme persistent precipitation is becoming increasingly common globally, and persistent extreme regional precipitation events (PERPEs) pose a particularly serious threat to humans and environmental systems. This study investigated total precipitation (TP), daytime precipitation (DP), and night‐time precipitation (NP) in southwest China (SWC) during 1961–2019. The occurrence of TP, DP, and NP was analysed under the conditions of persistence over 1–5 days, temporal persistence over >2 days, and temporal nonpersistence over ≤2 days, and spatiotemporal overlap for at least 3 days (i.e., a PERPE) using the objective identification technique for regional extreme events. The results indicated the following. (a) Annual maximum daily precipitation ≥200 (100) mm in terms of TP (NP) was recorded mainly in the Sichuan Basin (SCB) and eastern parts of the Yunnan–Guizhou Plateau (YGP), and it occurred mostly in summer. For DP, annual maximum daily precipitation of ≥100 mm was recorded throughout SWC, and it occurred mainly in winter in the Henduan Mountains, summer in the SCB, and spring in western parts of the YGP. (b) The magnitudes of NP and DP differed for events persisting for 1–5 days. The average amount of precipitation with temporal persistence increased during 1961–2019 for TP, DP, and NP. However, the frequency of occurrence of events with temporal persistence increased more in comparison with that of events with temporal nonpersistence. Overall, the frequency of occurrence of events with temporal persistence or temporal nonpersistence in the western SCB and eastern YGP increased more for TP and NP than for DP. (c) In the study period, 22, 44, and 4 PERPEs were detected for TP, NP, and DP, respectively, occurring mainly in the SCB, indicating that TP was dominated by night‐time PERPEs. These findings improve understanding of PERPEs changes in SWC and provide scientific support for implementation of measures intended to prevent and mitigate extreme flood events and waterlogging.