Influence of Teleconnection Factors on Extreme Precipitation in Henan Province under Urbanization

Urban extreme precipitation is a typical destructive hydrological event. However, the disaster-causing factors of urban extreme precipitation in Henan Province have rarely been discussed. In this study, daily precipitation data of 11 stations covering a disaster-affected area in “21.7” rainstorm event from 1951 to 2021 and hundreds of climatic indexes set were selected. First, the Granger causality test was adopted to identify the dominant teleconnection factors of extreme precipitation. Then, the effects of teleconnection factors on extreme precipitation in four design frequencies of 10%, 1%, 0.1%, and 0.001% in typical cities of Henan Province were analyzed by using regression and frequency analysis. Finally, the future variation was predicted based on CMIP6. The results show that: (1) The West Pacific 850 mb Trade Wind Index, Antarctic oscillation index, and other factors exert common influence on disaster-affected cities. (2) Teleconnection factors are the dominant force of urban extreme precipitation in most cities (50.3–99.8%), and area of built-up districts, length of roads, area of roads, and botanical garden areas are the key urbanization indicators affecting extreme precipitation. (3) In the future scenarios, the duration and intensity characteristics of urban extreme precipitation will increase, and the growth rate will increase monotonically with the recurrence period.