Detecting Spatiotemporal Shifts in Precipitation Core Regions Using a Centroid-Based Identification Method and Its Application in China

Abstract The spatiotemporal regime of precipitation determines the level and variation of regional water resources, influencing management responses and adjustments. Identifying regional precipitation patterns is crucial for recognizing and predicting hydrological regimes. This paper proposes a new centroid-based cooperative identification method for regional precipitation and its spatiotemporal shifts. This method was verified by comparing the spatial shifting trends between the centroids of regional annual precipitation and the contour lines of mean annual precipitation in four regions of China, using the Köppen climate classification method. The results indicate that within the Cwa climate region, the average latitude of the centroid increased by 5.8%, while the average longitude increased by 0.51% in recent years. In the Dfc climate region, the average latitude of the centroid increased by 0.38%, and the average longitude by 0.63% over the same period. These centroids showed a northward shifting tendency in the mentioned climate regions. Differently, in the Dwa region, the centroid’s average latitude shifted from 42.29 degrees to 41.57 degrees, while the average longitude shifted from 105 degrees to 110.03 degrees. Additionally, in the HG region, the centroid’s average latitude shifted from 32.06 degrees to 32.58 degrees, and the average longitude from 93.95 degrees to 97.73 degrees. Furthermore, on an interdecadal time scale, the precipitation centroids within the four climate zones consistently exhibit a northward shift. Overall, the centroids have shown a northward movement in China in recent years. This paper provides a theoretical basis for water resource management and hydrological forecasting, aiding in the analysis of the spatiotemporal transfer trends of precipitation in the context of climate change.