利用1951-2007年NCEP/NCAR再分析资料及中国国家气候中心160站降水和环流特征指数,研究了近57 a来夏季平均的西太平洋副热带高压面积指数的气候变化特征及其对同期中国降水的影响.结果表明,在全球变暖的气候背景下,夏季副热带高压面积也表现出增大趋势,其中20世纪60年代中期和20世纪末显著增强,并呈现出准20 a的年代际周期变化特征.各周期中,中国同期降水及流场均出现较大调整:随着西太平洋副热带高压面积长期趋于增大,东亚夏季风异常偏弱,降水分布由"北多南少"转为"北少南多",而降水线性增长的区域则呈现出较上一周期明显北移的特征.%Using the NCEP/NCAR reanalysis from 1951 through 2007,the precipitation data at 160 sta-tions and the circulation index in the same period released by the National Climate Center of China,wehave investigated in the present paper the abrupt changes in area of summertime mean West Pacific Subtropical High(WPSH)and interdacadal variations in summer precipitation over China during the last 57 years.The results suggest that under the background of the global warming,the area of WPSH also showed an apparent increasing trend especially in the mid-1960s and the late 1990s(i.e.an inter-decadal change character of quasi-20 years).In the three quasi-20 year periods of the 1950s-1960s,the 1920s-1980s and the 1990s-2007,summer precipitation and atmospheric circulation over China were obviously changed:along with successive increase in the area of WPSH,the East Asian monsoon became anomalously weak;and the precipitation pattern over China changed from positive anomaties in Southern China-negative anomaties in Southern China in the 1950s-1960s to negative anomaties in Northern China-positive anomaties in Southern China in the 1990s-2007;and the area where the pre-cipitation linearly increased also showed a northward migration trend.
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