Abstract: Urbanization and other human activities contribute to the changing climate on regional and global scales, including the increasing occurrence of extreme precipitation events in China in the past decades, but the relative importance of these urbanization, as compared to climatic factors, remains unclear. The main goal of this study was to determine the relative contributions of urbanization to the altered spatiotemporal patterns of extreme precipitation in China during the past several decades. We used daily precipitation data from 544 meteorological stations in China from 1961 to 2010, and gets the thresholds of extreme rainfall of each station by using the developed method called moving spatial percentile (MSP). We uses the ratio of extreme precipitation to total precipitation as the indicator so as to reflect the intensity of extreme precipitation. Based on the DMSP/OLS night light datasets, the urbanization levels of meteorological stations are divided into six grades. Then we use MSP and moving spatial anomaly to quantify the impact of urbanization on the intensity of extreme precipitation by doing a series of correlation analysis. The results show that the spatial pattern of extreme precipitation intensity derived from MSP is more distinguishable. Urbanization make the threshold of extreme precipitation increased by 1.68% and there is a significant linear correlation between extreme precipitation intensity and urbanization level, namely extreme precipitation intensity will increase by 0.62% when the urbanization level increases by one grade. Our results suggest that the substantial increase in extreme precipitation across much of China during the past five decades is likely triggered by local and regional urbanization process. Our results call for a better understanding of local and regional anthropogenic impacts on climate, and the exacerbated extreme climate events as a potential consequence of urbanization. This highlights the need to explore more deeply the specific roles of a range of anthropogenic processes and their relative contributions to extreme precipitation at regional scales.
Key words：extreme precipitation; moving spatial percentile; moving spatial anomaly; DMSP/OLS; urbanization; China