1979~2017年冬季西伯利亚高压变化特征及其对西南地区气温的影响

Variation Features of Siberian High in Winter and Its Impact on Temperature of Southwest China

利用美国国家环境预测中心–国家大气研究中心(NCEP-NCAR)和欧洲中期天气预报中心(ECMWF)的再分析资料,基于经验正交函数(EOF)、奇异值分解(SVD)、回归分析及合成分析等方法,文章对西伯利亚高压的年际及年代际变化特征进行分析,并揭示其与我国西南地区气温的关系。结果表明:冬季西伯利亚高压指数存在明显的年代际变化。通过强度指数、移动指数和面积指数的年际变化特征可以看出,西伯利亚高压中心强度增加(减弱)时,面积扩大(缩小),且向南、向东扩张(收缩)。分析西伯利亚高压强度和西南地区的气温,发现西南地区气温反位相的变化与西伯利亚高压的强度指数关系密切。进一步分析其影响机制可知,由于西伯利亚高压的强度变化导致西南地区上空环流场异常,从而使得西南地区气温异常。

Using National Centers for Environmental Prediction-National Center Atmospheric Research (NCEP-NCAR) and National Centers for Environmental Prediction-National Center Atmospheric Research (ECMWF) reanalysis data, based on methods of Empirical orthogonal function, singular value decomposition, regression analysis and composite analysis, the paper analyzes the variation features of Siberian High (SH) and explores the relationship between Siberian high pressure and the temperature of southwest China. The result shows that Siberian high indexes have significant interdecadal variations. From analysis on the interannual variation characteristics of intensity index, mobility index and area index, it indicates that the area expands to the south and east when the central intensity of the Siberian high increases. Analyzing the Siberian High intensity and southeast temperature, we find that the intensity anomalies of temperature are closely related to the Siberian high intensity. When the Siberian high is strong (weak), the temperature in the east of southwest China is decreasing (increasing) and the temperature in the west is increasing (decreasing). Further analysis of the influence mechanism shows that the intensity change of Siberian high leads to the abnormal circulation field over the southwest China, which results in the abnormal temperature.