我国南方地区初秋气温的年际变化特征及影响因子分析

利用1979–2021年NCEP2.5°×2.5°、MOHC1°×1°海洋等资料，通过经验正交函数（EOF）分解、合成分析和相关分析等方法,分析了我国南方地区初秋气温的年际变化特征及其相关的大气和海洋异常。结果表明：（1）我国南方地区初秋气温主要表现为一致变化型和经向偶极变化型两种模态。（2）一致变化空间型主要受到高纬度西伯利亚高压和东亚大槽以及中低纬度地区的副热带高压和近地面风的共同影响，而经向偶极变化型则主要受到我国东北地区与我国长江下游流域对流层位势高度反位相变化的影响。（3）一致变化空间型与前期冬季我国邻近海域以及赤道印度洋和东太平洋地区海温异常、鄂霍茨克海和拉布拉多海海冰异常有关，经向偶极变化型则与前期冬季赤道中东太平洋的海温异常、鄂霍茨克海和巴伦支海海冰异常有关。

Interannual Variation Characteristics and Impact Factors of Early Autumn Temperature in Southern China

Based on the atmospheric and oceanic data from 1979 to 2021, the interannual variation characteristics of early autumn temperature in southern China and the related atmospheric and oceanic anomalies were analyzed by empirical orthogonal function (EOF) decomposition, composite analysis and correlation analysis. The results showed that: (1) The temperature in early autumn over southern China exhibits two leading spatial patterns: one is a spatially uniform pattern and the other is a meridional dipole pattern. (2) The spatially uniform pattern is mainly influenced by the anomalous geopotential height over Siberia and the East Asian trough at high latitudes, as well as subtropical high and near-surface wind in mid-lower latitudes, while the meridional dipole anomaly pattern is affected by the antiphase change of tropospheric geopotential height in Northeast China and the lower reaches of Yangtze River in China. (3) The spatially uniform anomaly pattern is related to the sea surface temperatures(SSTs) anomalies in the adjacent seas of China, the equatorial Indian Ocean and the eastern Pacific Ocean, together with the sea ice anomalies in the Sea of Okhotsk and Labrador; while the meridional dipole pattern is related to the SSTs anomalies in the equatorial southern Pacific Ocean and the sea ice anomalies in the Sea of Okhotsk and Barents in the preceding winter.