澳大利亚热低压的年际变化对中国南方地区冬季降水的可能影响途径  

Possible Mechanism About Effect of Interannual Variation of Australia Summer Heat Low on Winter Rainfall in Southern China

作　　者：胡姗姗 刘倪[2] 张蓬勃 熊世为 金华星 龚年祖 郁凌华 

机构地区：[1]安徽省滁州市气象局,安徽滁州239000 [2]安徽省气象台,安徽合肥230061 [3]江苏省南京市气象局,江苏南京210009

出　　处：《干旱气象》2015年第3期371-378,共8页Journal of Arid Meteorology

基　　金：安徽省气象局科技发展基金"短期温度降水多模式集成预报(KM201404)"资助

摘　　要：南半球大气环流是全球大气环流的重要组成部分，是影响气候变化和东亚季风系统的一个重要因素，澳大利亚热低压作为东亚和印尼-北澳冬季风环流系统的重要组成成员之一，其强度变化对中国南方地区冬季降水有重要影响。本文统计了1961～2013年澳大利亚热低压强度的异常年份，利用NCEP／NCAR再分析资料和中国气象局提供的1951年以来160个标准站逐月降水资料，找出澳大利亚热低压的年际变化与中国南方地区冬季降水之间的联系，并对澳大利亚热低压影响中国南方冬季降水的可能途径进行分析。结果表明：在北半球冬季，澳大利亚热低压对中国南方地区冬季降水有重要影响，当澳大利亚热低压加深（中心气压值降低）时，中国南方地区降水偏少；相反，当其强度减弱（中心气压值升高）时，中国南方地区降水增加。当澳大利亚热低压异常偏强时，500hPa东亚大槽偏强，哥0热带高压减弱，冬季风偏强，中国南方地区处于异常偏北气流影响，且存在异常的下沉气流，水汽输送条件差，不利于冬季降水。此外，在赤道附近形成异常的西风带，并通过侧向耦合作用，致使南海附近形成异常的气旋性环流，进而在南方地区的中低层出现异常的偏北风，不利于南方地区冬季降水；当澳大利亚热低压偏弱时，情况则相反。The Southern Hemisphere （SH） atmospheric circulation is an important part of the global atmospheric circulation and a key factor to influence the global climate change and East Asian monsoon system. In winter of the Northern Hemisphere （NH） , the intensity changes of Australia summer heat low which is one of East Asia and Indonesia - Northern Australia winter monsoon systems in the low level has great influence on winter rainfall in Southern China. Based on the monthly precipitation at 160 weather stations in China since 1951 and NCEP/NCAR reanalysis data, the anomalous intensity events of Australia summer heat low from 1961 to 2013 were se- lected, firstly. The relation between the interannual change of Australia summer heat low and winter precipitation in southern China was found, and on this basis the possible influencing mechanism of the Australia summer heat low on winter rainfall in southern China also was analyzed. Results showed that the Australia summer heat low had significant effect on winter rainfall in southern China in NH winter, and there was a negative correlation between them. When the Australia summer heat low was stronger than normal, the precipitati- on in southern China would be significantly less. Conversely, when it was weaker, the precipitation would be more. When the Australia summer heat low was anomalous stronger than normal, the East Asia Trough on 500 hPa strengthened, the subtropical high weakened, winter monsoon enhanced, and the region in southern China was influenced by the anomalous northerly airflow and downward airflow, the water vapor transport was poor, so it was not conducive to rainfall. In addition, the anomalous cyclonic circulation over the South China Sea formed due to the anomalous westerlies near the equator through the lateral coupling effect, and then the abnormal northerly wind appeared in the low and middle layer of the southern area, which was not help to rainfall in winter. When the Australia summer heat low was anomalous weaker than normal, it was the o

关 键 词：澳大利亚热低压 中国南方冬季降水 可能影响途径 

分 类 号：P426.616[天文地球—大气科学及气象学]