青藏高原冬季风强弱年中国气候对比分析
The Comparative Analysis of the Climate Situation in China on Strong and Weak Plateau Winter Monsoon Year
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摘要: 本文选取1984~2013年NCEP/NCARII月平均再分析资料和,及全国160个台站月平均气温和降水量资料,使用由散度定义的青藏高原季风指数,以1月为冬季代表月,确定高原冬季风强弱代表年。通过相关分析和合成分析,详细分析了青藏高原冬季风强弱年份,东亚大气环流和我国气候的差异。结果表明:(1)高原冬季风强弱伴随东亚大气环流的异常,当高原冬季风偏强时,高原上空的冷低压加强,辐散下沉运动加大,中高纬地区的槽脊加深,而低纬地区有一气旋性环流生成;(2)高原冬季风强弱年我国同期气候差异明显,高原冬季风偏强年的冬季,新疆北部、华北中部等地降水偏多,四川盆地、长江中下游等地降水偏少,冬季气温大部份地区偏高,云南、黑龙江等地略偏低。(3)高原冬季风的影响具有滞后效应,高原冬季风强弱年的夏季,大气环流和我国气候明显不同,强年高原热低压和高纬地区的槽脊减弱,西太平洋副高偏北偏强,长江中下游、华南等地降水明显偏多,长江中上游、内蒙等地降水明显偏少。Abstract: In this research, using the NCEP/NCARII monthly reanalysis data and 160 weather station data in china from1984 ~ 2013, and using the Plateau Monsoon index defined by the divergence to define the strong and weak winter (January) monsoon year. Based on the selected-year, this research analysis the basic characteristic of the strong and weak monsoon years, the difference of the circulation in East Asia and China at the strong and weak monsoon years. The results show: (1) the performance of the plateau winter monsoon is along with the anomalous circulation in East Asia as well as in China. In the winter time of the strong plateau winter monsoon year, the cold-core cyclone above the plateau gets stronger, the trough-axis and ridge-axis gets extended over the mid and high latitudes area, and a cyclone appears over low latitude area; (2) the difference of the climate situation in the strong and weak monsoon years is quite obvious: in the winter time of the strong monsoon year, the precipitation over northern Xinjiang Province, the middle area of northern China is relatively higher while Sichuan Province, and the around middle to lower area of Yangtze River is relatively lower. As for the temperature, most parts of China is relatively high, some parts of Yunnan and Heilongjiang Province is relatively low. (3) There is hysteresis phenomenon of the impact of winter monsoon, the weak and strong winter monsoon years, the atmospheric circulation in the summer time over China is quite different, in the summer time of strong winter monsoon years, the thermal depression above the plateau gets weaker, the trough-axis and ridge-axis gets curtailed over the mid and high latitudes area; the position of subtropical anticyclone is northward, and it is stronger than usual; the precipitation along middle to lower area of Yangtze River and some parts of southern China is relatively higher while the higher to middle area of Yangtze River and Inner Mongolia is relatively lower.