2012年冬春季高原积雪异常对亚洲夏季风的影响  

Impact of Tibetan Plateau Snow Cover Anomaly on Asian Summer Monsoon in 2012

作　　者：竺夏英[1] 陈丽娟[1] 李想[1] 

机构地区：[1]国家气候中心,中国气象局气候研究开放实验室,北京100081

出　　处：《气象》2013年第9期1111-1118,共8页Meteorological Monthly

基　　金：国家自然科学基金项目(41275073);国家科技支撑计划项目(2009BAC51B05);公益性行业(气象)科研专项(GYHY201206017);中国气象局短期气候预测创新团队项目共同资助

摘　　要：利用罗格斯大学积雪遥感资料、NCEP/NCAR再分析格点资料和NOAA陆地降水分析数据PREC/L,从2011/2012年冬春季青藏高原积雪偏多现象与亚洲夏季风的观测事实与以往研究结果不一致出发,诊断分析了2011/2012年冬春积雪与亚洲夏季风的可能联系。结果表明:2012年春季和前期冬季,青藏高原主体上空对流层主要为气旋性环流距平且气温偏低,这与积雪偏多年的环流特征一致。尤其在90°E以西,自青藏高原到热带地区,前期冬春季对流层中部气温表现为北冷南暖的距平特征,有利于夏季自热带印度洋到高原温度梯度偏弱,造成南亚夏季风偏弱。但是在90°E以东的高原东部到东亚地区及其南侧的低纬度地区,对流层温度距平为北正南负型,温度梯度偏弱,有利于亚洲东南部大气环流冬夏季节转换偏早,南海夏季风爆发偏早,东亚夏季风偏强,这种环流特征受到高原以外的其他外强迫信息的影响。2011/2012年冬春季积雪偏多特征可能对南亚夏季风偏弱有重要贡献,而对东亚夏季风的影响不明显。The East Asain summer monsoon was stronger in 2012, though the Tibetan Plateau （TP） snow cover extent was anomalously larger than the climate mean in the preceding spring and winter, which is in- consistent with the results of previous studies. This paper made an effort to investigate the possible rela- tionship between the TP snow cover from winter 2011 to spring 2012 and the following Asian summer monsoon, using the monthly mean snow cover extent data from Rutgers University Global Snow Lab, NCEP/NCAR reanalysis monthly average data, and the monthly data set of NOAA^s Precipitation Recon- struction over Land （PREC/L）. The findings suggest that the TP was covered mainly by an anomalous cy- clone with lower ＇temperature in the mid-troposphere in spring 2012 and the previous winter, which agreed with the features of larger snow cover years. Particularly to the west of 90~E, the mid-tropospheric tem- perature anomalies from the TP to the tropical Indian Ocean were negative in the north and positive in the south from winter to spring, conducive to the weaker meridional temperature gradient there in summer and thus to the weaker South Aisan summer monsoon. However, to the east of 90°E, the mid-tropospheric temperature anomalies from East Asia to the tropics were positive in the north and negative in the south inwinter and spring, favorable for the earlier seasonal transition from winter to summer in the southeastern Asia, the earlier onset of the South China Sea summer monsoon, and also the stronger East Asian summer monsoon. They were more influenced by other forcings than the TP. Therefore, the fact of more TP snow cover from winter 2011 to spring 2012 probably made a significant contribution to the following weaker South Asian summer monsoon, and had less impact on the East Asian summer monsoon in 2012.

关 键 词：青藏高原 积雪 温度梯度 亚洲夏季风 

分 类 号：P461[天文地球—大气科学及气象学]