Characteristics of the extreme precipitation and its impacts on ecosystem services in the Wuhan Urban Agglomeration

Summer extreme precipitation is one of the most frequent, intense, and influential extreme weather events that occurs frequently in the Wuhan Urban Agglomeration (WUA). Preventing meteorological disasters and coping with climate change necessitate understanding the characteristics and causes of extreme precipitation and its impact on ecosystems. In this study, the spatiotemporal characteristics of summer extreme precipitation in the WUA are analysed from 1961 to 2020. Then, NCEP reanalysis data and the relevant circulation index are used to explore the causes of extreme precipitation. Finally, how extreme precipitation influences key ecosystem services, such as water yield, water regulation, and soil conservation, is investigated. The results reveal that (1) extreme precipitation in the WUA has shown an obvious upwards trend over the past 60 years. Huanggang, Xianning, Huangshi, Wuhan, and E'zhou city demonstrate the highest values. The extreme precipitation increased significantly after 1980s, especially the R97.5P and PRCPTOT with change rate of 12.1 mm/10a and 18.82 mm/10a respectively. (2) Atmospheric circulation variation is a dominant factor affecting extreme precipitation in the WUA and causes the meridional distribution of the "+ - +" wave train in eastern China. The intensity and location of the Western Pacific subtropical high are closely related to extreme precipitation. Furthermore, the weakening of the East Asian summer monsoon circulation is also conducive to the occurrence of extreme precipitation. (3) The spatial distribution of water yield and runoff retention in abnormal extreme precipitation years are similar to the variation patterns of the total amount of extreme precipitation. Water yield and runoff retention in high-value extreme precipitation years are higher than that in low-value extreme precipitation years, while soil conservation shows no difference. In addition, ecosystem services have a synergistic relationship in high-value areas and a trade-off relationship in low-value areas. This study can contribute to the understanding of extreme precipitation in the WUA and its interaction with ecosystem services.