贵州省汛期降水特征及强降水过程分型研究

【目的】为探究贵州省汛期降水的时空分布特征及演变规律。【方法】利用贵州省81个气象观测站1981—2020年汛期降水资料，采用EOF、REOF及交叉小波分析等方法对贵州省汛期降水时空特征进行分析及强降水过程分型研究。【结果】贵州省1981—2020年汛期平均降水量为924.9mm，降水量在682.7~1194.1mm，呈显著上升趋势，上升速率为16.94mm/10a。贵州汛期降水大体上呈现西南向东北递减的趋势，强降水过程次数及持续天数分布及波动变化与汛期降水基本一致。【结论】贵州省汛期降水分布不均，具有显著的年代际变化。贵州省汛期强降水空间场主要有全省一致型、东西反向型和南北反向型3种典型模态。经REOF方法可将贵州省细分为3个强降水区域，根据环流场分析，又可进一步划分为东部型强降水（I型和III型）与西部型强降水（II型），各类型强降水落区受500hPa环流分布情况以及850hPa水汽来源与强度的影响。

Characteristics of Precipitation and Classification of Heavy Precipitation Processes during the Rainy Season in Guizhou Province

To explore the spatial and temporal distribution characteristics and evolution patterns of precipitation during the rainy season in Guizhou Province, based on the precipitation data of 81 meteorological stations in Guizhou Province during the rainy season from 1981 to 2020, the spatio-temporal characteristics of the rainy-season precipitation are analyzed and the classification of heavy precipitation processes in Guizhou Province are conducted by means of EOF, REOF and cross wavelet analysis methods. The results show that the average precipitation during the rainy season in Guizhou Province from 1981 to 2020 is 924.9mm, and the precipitation varies from 682.7 mm to 1194.1 mm, showing a significant upward trend with a rising rate of 16.94 mm per decade. The precipitation in Guizhou Province during the rainy season generally shows a decreasing trend from southwest to northeast, and the distribution and fluctuation of the frequency and duration of heavy precipitation processes are basically consistent with those of the rainy-season precipitation. Thus, it is seen that the precipitation in Guizhou Province during the rainy season is unevenly distributed with significant interdecadal variations. The spatial field of heavy precipitation during the rainy season in Guizhou Province has three typical modes, namely, the overall consistency type, the east-west reverse type, and the north-south reverse type. By REOF method, Guizhou Province can be spatially subdivided into three heavy precipitation regions. According to the analysis of the atmospheric circulation features, heavy precipitation can be further divided into the eastern type (Type I and Type III) and the western type (Type II). Each type of heavy precipitation region has the influence from the distribution of 500 hPa atmospheric circulation and the source and intensity of 850 hPa water vapor.