Spatiotemporal variation characteristics of precipitation and urbanization effects in Shenzhen from 1960 to 2019

To explore the evolution characteristics of precipitation in megacities under the changing environment and the influence of human activities. Shenzhen City was selected as the study area. Based on daily precipitation from 10 rainfall stations from 1960 to 2019. The TFPW-MK and EOF methods were used to analyze the spatiotemporal evolution characteristics of precipitation. Results indicate that: (a) The precipitation in Shenzhen shows an insignificant upward trend. The changing trend of precipitation has certain spatial heterogeneity. The precipitation at the western stations shows a downward trend. The oscillation period of Shenzhen's precipitation indicators is about 10-20 years and the year of abrupt change in precipitation was 1991. (b) The precipitation indicators of different physical meanings in Shenzhen have similar distribution modes. The first main mode shows global consistency, showing that the precipitation is either rainy or less rainy, and reflects that the precipitation center has changed from the northwest before 1990 to the southeast after 1990. The second main mode is 'East-West' reverse distribution characteristics. (c) Urbanization has a significant impact on the distribution of precipitation in Shenzhen and has an enhancing effect on precipitation. The smaller the time scale, the stronger the rainfall-enhancing effect of urbanization on extreme precipitation.