An Index of East Asian Winter Monsoon Applied to the Description of China's Mainland Winter Temperature Changes

作者：Zhu Yanfeng^*

来源：Acta Meteorologica Sinica, 2008, 22(4): 522-529.

• index of East Asian winter monsoon
• China's mainland
• winter temperature changes

Using the NCEP/NCAR. reanalysis data (Version 1.0) and the observation data of China from January 1951 to February 2007, a new index of East Asian winter monsoon circulation (I(EAWM)) was defined based on the comparison of previous different winter monsoon indices and circulation factors influencing the winter climate over China. Its relationships with winter temperature over China and large-scale circulation were analyzed. Results show that I(EAWM) can successfully describe the variation of China's mainland winter temperature and the East Asian winter monsoon (EAWM) system. This index reflects the integrated effect of the circulations over high and low latitudes and the thermal difference between the continent and the ocean. While in the previous studies, most monsoon indices only describe the single monsoon member. The I(EAWM) is a good indicator of the intensity of the EAWM. Positive values Of I(EAWM) correspond to the strong EAWM, the stronger Siberian high and East Asian trough than normal, and the strengthening of the meridional shear of 500-hPa zonal wind between high and low latitudes over East Asia, and therefore, the southwaxd cold advection becomes stronger and leads to the decrease in surface temperature over China; and vice versa. The I(EAWM) inter decadal change is obviously positive before the mid-1980s, but negative since the mid-1980s, in good agreement with the fact of the winter warming in China after 1985.

• 出版日期2008
• 单位国家气候中心