lnterannual and lnterdecadal Variability of East Asian Acas and Their Impact on Temperature of China in Winter Season for the Last Century

The interannual and interdecadal variability of the Siberian High (SH) and the Aleutian Low (AL) from aspects of strength and location for the past one hundred years as well as their possible relations with temperature changes over mainland China are investigated. The data sets used are the historical sea level pressure for 1871-1995 and surface air temperature (SAT) over China in the last 100 years. The results show that the SAT in different regions over China, central strength of the SH and the AL, the south-reaching latitude of the 1030 hPa contour of the SH and the pressure gradient between the SH and the AL experienced two obvious changes during this period. One occurred in the 1920s, with a more prominent one in the 1980s. These variations are closely linked with the change of winter temperature over China in the interdecadal timescale. In the last 50 years, there is a remarkable interannual correlation between the strength of Active Centers of Atmosphere (Acas) and the winter temperature of northern and eastern regions in China. The abrupt change of Acas in the 1980s is consistent with the rising of the SAT in China. Since the late 1980s, the atmospheric circulation is experiencing a remarkable modulation, which may cause the interdecadal transition of warming trend.