The Comparative Analysis of the Climate Situation in China on Strong and Weak Plateau Winter Monsoon Year

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.