冬季亚洲大陆年际热力差异与中国气候的关系

Relationship between interannual variation of wintertime thermal contrast over Asian continent and the climate in China

利用DB16小波对50 a来南亚—东北亚热力差异时间序列进行分析,其周期变化主要集中在3.5 a以下的高频振荡时域内,其次年代际变化也是相对明显的。在此基础上通过尺度分离方法,将亚洲大陆热力差异中的年际和年代际时间尺度进行分离,进一步研究了年际尺度上亚洲大陆热力差异的变化特征及其与中国夏季降水的关系。结果表明年际尺度上亚洲大陆热力差异与亚洲冬夏季风和中国夏季降水同样有一些联系:强(弱)热力差指数年对应的冬夏季风存在差异,中国夏季降水分布类似于第1(3)类雨带。另外,强(弱)指数年夏季东亚季风涌、对流活动分布等的变化均呈现出有利于中国北方降水偏多(偏少)的特征。

We analyzed the WSAT thermal contrast index series using DB16 wavelet.The calculation results indicated that the periodic variation was mainly less than 3.5 a and the interdecadal variation was also remarkable.By scale separative method the variation characteristics both on interannual and interdecadal scales of wintertime thermal contrast over Asian continent were separated.After the separation,we analyzed the interannual variations of thermal contrast over Asian continent areas and relationship between thermal contrast and summer precipitation in China.The results showed that on interannual scale the relationship between variation of wintertime thermal contrast over Asian continent and summer precipitation in China was apparent.In strong（weak） thermal contrast index years,the East Asian winter and summer monsoon also had some difference and the distribution of China summer rainfall was similar to the first（third） kind of rain belt.Moreover,the variations of summer monsoon surge and convective activity both showed significant characteristics which were beneficial to more（less） summer precipitation in north part of China.