北美洲冬季冷空气对南美洲夏季降水异常影响的研究  

Study on impacts of winter cold air over North America on summer precipitation anomaly over South America

作　　者：梁嘉俊 孙即霖 LIANG Jiajun;SUN Jilin(College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao 266100, China;Key Laboratory of Physical Oceanography (Ocean University of China), Ministry of Education, Qingdao 266100, China)

机构地区：[1]中国海洋大学海洋与大气学院,山东青岛266100 [2]中国海洋大学物理海洋教育部重点实验室,山东青岛266100

出　　处：《海洋气象学报》2020年第2期62-70,共9页Journal of Marine Meteorology

基　　金：国家自然科学基金重点项目(41430963);国家自然科学基金项目(41276012)。

摘　　要：利用1981—2017年NCEP/NCAR再分析资料和ECMWF再分析资料,研究了北美洲冬季高纬度冷空气对南美洲夏季降水异常的影响。结果表明,北美洲冬季高纬度冷空气通过影响向南越赤道气流的强弱,影响南美洲热带辐合带(intertropical convergence zone,ITCZ)位置和强度的变化,进一步引起南美洲天气的变化。北美洲冬季冷空气的南下过程能够引起80°~70°W的向南越赤道气流明显加强,导致2011年南美洲热带辐合带的位置异常偏南,强度异常偏强,是造成降水异常偏多的重要成因。通过相关分析发现北美洲冬季冷空气对南美洲ITCZ位置的影响更明显。Based on the NCEP/NCAR reanalysis data and ECMWF reanalysis dataset from 1981 to 2017,the impacts of the winter cold air over high-latitude areas in North America on the summer precipitation anomaly over South America are studied.The results show that the winter cold air over high-latitude areas in North America influences the location and intensity of the intertropical convergence zone(ITCZ)by influencing the intensity of the southward cross-equatorial flow,which further affects the change of weather in South America.The southward intrusion of winter cold air over North America can significantly strengthen the southward cross-equatorial flow in the area between 80°W and 70°W,resulting in the abnormally southward and strong ITCZ in South America in 2011,which is an important factor of the abnormally more precipitation.The correlation analysis shows that the winter cold air over North America has more significant influence on the location of ITCZ in South America.

关 键 词：热带辐合带 冷空气 越赤道气流 降水异常 

分 类 号：P426.6[天文地球—大气科学及气象学] P461