Evolution Characteristics of Annual Precipitation and Intra-Annual Allocation in Guangdong Province from 1958 to 2023

Characteristics of precipitation and its intra-annual allocation are the key factors triggering regional floods, and clarifying the spatial and temporal variations of precipitation concentration can provide a theoretical basis for regional flood control planning and water resources management. In order to analyze the evolution characteristics of annual precipitation and its intra-annual allocation in Guangdong Province, the daily precipitation data from National Meteorological Stations in Guangdong Province from 1958 to 2023 were used, and the distribution characteristics of precipitation concentration in Guangdong Province were quantitatively characterized based on the annual concentration index (ACI) formula. In addition, the Mann-Kendall (MK) trend test, Sen's slope trend analysis, inverse distance weighting, and Kriging interpolation methods were comprehensively adopted to study the temporal and spatial evolution characteristics of annual precipitation and ACI in Guangdong Province. The results show that: The spatial distribution of annual precipitation in Guangdong Province is distinctly geographical, showing a trend of "small precipitation in northern, eastern, and western regions and large precipitation in southern and central regions". The spatial distribution of ACI in Guangdong Province shows a distribution pattern of "low ACI in northern Guangdong and high ACI along the coast", with a gradual decrease in spatial distribution from southwest regions to northeast regions. Overall, the annual precipitation in Guangdong Province shows a non-significant increasing trend, while the ACI shows a decreasing trend. The large-scale topography and urbanization process are the key factors affecting regional precipitation, while the interaction of environmental factors and human activities has a significant impact on the formation of annual precipitation and ACI distribution patterns.