秋季北大西洋马蹄型海温异常与初冬我国气温年际变化的联系  

Characteristics of North Atlantic Horseshoe Sea Surface Temperature Anomaly in Autumn and Relationship with Interannual Variation in Early Winter Temperature in China

作　　者：李忠贤[1,2] 王庭轩 曾刚[1,2] 邓伟涛[1,2] LI Zhongxian;WANG Tingxuan;ZENG Gang;DENG Weitao(Key Laboratory of Meteorological Disaster of Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD),Nanjing University of Information Science&Technology,Nanjing 210044;School of Atmospheric Sciences,Nanjing University of Information Science&Technology,Nanjing 210044)

机构地区：[1]南京信息工程大学气象灾害教育部重点实验室/气象灾害预报预警与评估协同创新中心,南京210044 [2]南京信息工程大学大气科学学院,南京210044

出　　处：《大气科学》2024年第3期1131-1143,共13页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金项目42175034、42175035。

摘　　要：本文基于Hadley中心的海表温度资料、全国160站气温资料以及National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR)的再分析资料,运用经验正交函数(empirical orthogonal function,EOF)分解和相关分析等多种统计方法,研究了1951~2020年秋季(9~11月)北大西洋海温年际异常的主要特征及其对初冬(12月)我国气温异常的影响。结果表明:秋季北大西洋海温异常EOF的第一模态是纽芬兰岛东南部海温为负(正)距平,北大西洋副极地和副热带及其东部海温为正(负)距平的马蹄型海温模态,方差贡献率为20.5%。研究表明,秋季北大西洋马蹄型海温异常与我国大部分地区初冬气温异常有显著的正相关关系,即秋季北大西洋马蹄型海温模态呈正位相时,我国大部分地区初冬气温偏高,反之,我国大部分地区初冬气温偏低。进一步分析表明,秋季北大西洋马蹄型海温异常能够持续到初冬。当秋季北大西洋马蹄型海温呈正(负)位相时,初冬北大西洋副极地和副热带海温异常通过加热(冷却)异常能够引起局地对流层上层的辐散(辐合)运动,并且激发出南、北两支Rossby波列。其中,北支波列由北大西洋副极地向东北方向传播至巴伦支海附近,然后沿西伯利亚向东南方向传播至我国上空;南支波列由北大西洋副热带向东传播至我国上空。在南、北支波列的影响下,我国上空对流层上层出现异常辐合(辐散),与之伴随的异常下沉(上升)运动使得我国上空云量减少(增加),到达地表的短波辐射增加(减少),同时地表向低层大气传输的长波辐射增加(减少),在非绝热加热的作用下,我国大部分地区气温偏高(偏低)。利用NCAR Community Atmosphere Model version 5.3(CAM5.3)模式模拟了北大西洋马蹄型海温异常对初冬大气环流、辐射强迫和气温的影响,模拟结果与观测资料统计分析结果基本一致,进一步表明该海温�Based on the sea surface temperature(SST)data of the Hadley Center,the temperature data of 160 stations in China,and the reanalysis data of National Centers for Environmental Prediction/National Center for Atmospheric Research(NCEP/NCAR),the interannual variability of the North Atlantic SST anomaly(SSTA)in autumn and its association with early winter temperature in China are studied using a variety of statistical methods,such as empirical orthogonal function(EOF)and correlation analysis.The results show that the first mode of North Atlantic SSTA EOF in autumn is the North Atlantic horseshoe(NAH)pattern with negative(positive)SSTAs in southeastern Newfoundland and positive(negative)SSTAs in the subpolar,subtropical,and eastern North Atlantic,which revealed a variance of 20.5%.A significant positive correlation was observed between NAH SSTA in autumn and early winter in most parts of China.Further analysis shows that NAH SSTA in autumn can persist until early winter.When NAH SST is in a positive(negative)phase in autumn,the heating(cooling)of NAH SSTA over the subpolar and subtropical regions in early winter can cause divergence(convergence)in the upper troposphere,and two Rossby wave trains are stimulated in the north and south branches.The north branch of the wave train propagates northeastward from the North Atlantic subpolar to the vicinity of the Barents Sea and then propagates southeast along Siberia to China.The south branch of the wave train propagates eastward from the subtropical North Atlantic to China.Convergence(divergence)occurs in the upper troposphere over China under the influence of the south and north branches of wave trains.Through the sinking(rising)movement,the total cloud cover in the above area is reduced(increased),the shortwave radiation reaching the surface has increased(reduced),and the longwave radiation transmitted from the surface to the lower atmosphere has increased(reduced).Furthermore,the temperature in most areas of China is abnormally high(low)under diabatic heating.The effects

关 键 词：北大西洋海温 初冬气温 非绝热加热 年际变化 

分 类 号：P461[天文地球—大气科学及气象学]