基于EOF的江西省秋季降水时空分布特征

基于1980—2020年秋季江西省83个气象观测站逐月降水数据，利用EOF方法分析了该地区秋季降水的时空分布特征。结果表明，江西省秋季降水场主要有4种类型，分别为全区型、北湿(干)南干(湿)型、西湿(干)东干(湿)型、中心湿(干)南北干(湿)型，累计贡献率为86.7%。1980—2020年，全区型和中心湿(干)南北干(湿)型降水呈增加趋势，而北湿(干)南干(湿)型和西湿(干)东干(湿)型降水呈下降趋势。其中全区型降水分布的年份占比75.6%，主要受大尺度大气环流的影响。北湿（干）南干（湿）型降水分布的年份占比17.1%，这是由于赣北地区受地形抬升作用，降水较多，而中南部在背风坡，降水较少，同时秋季赣北处于副热带高压边缘，且受到台风外围的影响，易发生降水，使得南北降水呈反相位变化。

Spatial and temporal distribution of autumn precipitation based on EOF in Jiangxi province

Based on the 1980-2020 monthly precipitation data of 83 meteorological stations in autumn in Jiangxi province, the spatial and temporal distribution characteristics of precipitation in autumn in Jiangxi province were analyzed by using EOF (Empirical Orthogonal Function). The results showed that the spatial distribution of precipitation in Jiangxi province presented four types: whole region wet (dry), north wet (dry) south dry (wet), west wet (dry) east dry (wet), central wet (dry) south and north dry (wet), with the cumulative contribution rate of 86.7%. From 1980 to 2020, the types of the whole region wet (dry) and the central wet (dry) south and north dry (wet) showed increasing trends, while the types of the north wet (dry) south dry (wet) and the west wet (dry) east dry (wet) exhibited decreasing trends. The precipitation distribution characteristics of the whole region wet (dry) accounted for 75.6%, which was mainly affected by large scale atmospheric circulation. The precipitation distribution characteristics of the north wet (dry) south dry (wet) accounted for 17.1%. Due to the uplift of topography, more precipitation occurred in northern Jiangxi, while the precipitation in the central and southern parts was less on the leeward slope. In autumn, northern Jiangxi was on the edge of subtropical high and affected by typhoon, so precipitation was easy to occur, making the difference between the north and the south showed an inverse phase change.