Ningaloo Nino/Nina与华南冬季降水异常的联系  

Association of Ningaloo Nino/Nina with winter precipitation anomaly in South China

作　　者：吴越[1,2] 曾刚 杨效业[1] 李忠贤 WU Yue;ZENG Gang;YANG Xiaoye;LI Zhongxian(Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters/Key Laboratory of Meteorological Disaster,Ministry of Education,Nanjing University of Information Science&Technology,Nanjing 210044,China;Climate Center of Sichuan Province,Chengdu 610072,China)

机构地区：[1]南京信息工程大学气象灾害预报预警与评估协同创新中心/气象灾害教育部重点实验室南京信息工程大学,南京210044 [2]四川省气候中心,成都610072

出　　处：《气象科学》2022年第1期24-32,共9页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(41831174,42175035,42175034);国家重点研发计划专项资助项目(2017YFA0603804)。

摘　　要：利用1979—2017年逐月平均的NOAA ERSST V3b海表温度资料、CN05.1降水资料以及NCEP/NCAR大气再分析资料,分析了Ningaloo Nino/Nina的基本特征及其与华南冬季降水异常的联系。结果表明,Ningaloo Nino/Nina是副热带东印度洋海温异常EOF第一模态,具有明显的年际变化特征和季节锁相特性。在扣除El Nino/La Nina的影响后,Ningaloo Nino/Nina与华南冬季降水异常存在着密切的联系,即Ningaloo Nino(Nina)年时,华南地区冬季降水增多(减少)。这种影响的可能机制是:Ningaloo Nino/Nina通过影响南支槽的强度变化进而影响华南冬季降水异常。Ningaloo Nino年冬季,澳大利亚西侧海表温度升高,对流增强,使南半球80°~100°E附近的Hadley环流上升支增强,造成经向环流异常,北半球低纬度地区形成一个异常的反环流圈,导致南支槽的增强。南支槽的强度与华南冬季降水呈正相关关系,南支槽强度偏强时,活跃的扰动向下游传播,槽前盛行的西南气流使得充足的水汽自孟加拉湾由西南向东北方向输入,为华南冬季降水偏多提供了条件,Ningaloo Nina年份的情形则与之相反。Based on 1979-2017 monthly Sea Surface Temperature(SST)data from NOAA ERSST V3b,CN05.1 precipitation data,and NCEP/NCAR reanalysis data,the variation of Ningaloo Nino/Nina and its association with winter precipitation anomaly in South China were investigated.Results suggest that Ningaloo Nino/Nina is the first EOF mode of SST anomaly in the subtropical East Indian Ocean with significant interannual variability and seasonal lock phase features.After deducting the effects of El Nino/La Nina,there is a close relationship between Ningaloo Nino/Nina and winter precipitation in South China,more(less)winter precipitation in South China during the Ningaloo Nino(Nina)year.The possible mechanism for this effect is that Ningaloo Nino/Nina affects winter precipitation in southern China by influencing the intensity of southern branch trough.An enhanced convection occurs in western Australia during the winter of Ningaloo Nino,and then results in an anomalous longitudinal circulation cell and anomalous counter-circulation cell in the lower latitudes of the northern hemisphere,which enhances the southern branch trough.The intensity of the trough in southern branch is positively correlated with the winter precipitation in southern China.When southern branch trough is strong,the active disturbance propagates downstream,and the prevailing southwesterly flow in front of the trough makes sufficient water vapor from the Bay of Bengal flowing from southwest to northeast,in favor of more winter precipitation in southern China,and vice versa for Ningaloo Nina years.

关 键 词：Ningaloo Nino/Nina 年际变化 南支槽 华南冬季降水 

分 类 号：P461.2[天文地球—大气科学及气象学]