南极海冰涛动及其对东亚季风和我国夏季降水的可能影响

Antarctica Sea-Ice Oscillation and Its Possible Impact on Monsoon of South Sea and China Summer Rainfall

利用NCEP 1973-2002年逐月南极海冰密集度格点资料,定义了具有跷跷板式变化规律的南极海冰涛动指数,分析了冬季南极海冰涛动指数与我国夏季降水及东亚季风爆发时间的关系.结果显示:南极海冰涛动指数与同期南极海冰密集度相关系数超过5%信度的格点数占南极海冰格点数的1/3,表明定义南极海冰涛动指数能够代表南极地区1/3海冰的变化区域.冬季南极海冰涛动指数和我国汛期(6-8月)降水距平百分比相关显著,正相关主要在长江流域及其以南地区,长江流域以北为负相关,相关系数均超过5%的信度.当冬季南极海冰涛动指数为负值时,南海季风爆发早,概率为11/14=79%;为正值时南海季风爆发晚,概率为12/15=80%.通过讨论冬季南极海冰涛动指数影响我国季风降水的可能过程,给出了概念模型.

Antarctic sea-ice oscillation index with a seesaw pattern is defined Using NCEP/NCAR reanalysis girds data of monthly Antarctica sea-ice concentration from 1973 to 2002. The Relationships between the index of winter and the summer precipitations in China as well as the onset date of the summer East Asia monsoon are presented. The study result shows that the grids of correlation coefficients passed 5 % confidence level between Antarctic sea-ice oscillation index and Antarctic sea-ice concentration are more than 1/3 of all grids of Antarctica sea-ice, that means the index can represent 1/3 sea-ice area. The winter index has a significant correlation with abnormal summer （June-August） precipitation in China. The area of positive correlation lies in the Yangtze River basin and its south, and that of negative correlation lies mainly in the north of Yangtze River basin. While the winter index is positive （negative）, the onset date of South China Sea monsoon is earlier （later）, with a probability of 79%（ 80 %）. Consequently, a conceptual model is given in term of discussing the possible process between the winter Antarctic sea ice and the monsoon precipitation in China.