Abstract:
Based on daily precipitation data from 46 meteorological stations in Sichuan Province from 1961 to 2024, temporal and spatial variation characteristics of rainy days frequency across spring, summer, autumn, and winter seasons were analyzed using methods including trend coefficient, empirical orthogonal function, and wavelet analysis.Results showed that, ① number of rainy days in different seasons of Sichuan Province showed a significant downward trend, with autumn and summer exhibiting the most significant reductions, followed by spring and winter.② Western Sichuan Basin, southwestern region of Sichuan Province, and junction of Sichuan, Guizhou, and Yunnan provinces constitute areas with high rainy day counts, most prominent in Ya'an City and Emeishan City.③ Seasonal variation in rainy day counts across Sichuan Province exhibit spatially simultaneous increase and decrease characteristics, while temporally displaying three distinct features: entire region consistent type, east-west differences, and north-south differences.④ Periodic variations in seasonal rainy days in Sichuan Province mainly has two characteristic time scales, with most patterns appearing as multiple periodic scales nested with each other, showing strong local characteristics.