冬季欧亚中高纬大气低频振荡的传播及其与欧亚遥相关型的关系  

Propagation of Low-Frequency Oscillation over Eurasian Mid–High Latitude in Winter and Its Association with the Eurasian Teleconnection Pattern

作　　者：杨双艳[1,2,3] 武炳义[2] 张人禾[2] 周顺武[3] 

机构地区：[1]深圳市国家气候观象台,深圳518040 [2]中国气象科学研究院,北京100081 [3]南京信息工程大学气象灾害省部共建教育部重点实验室,南京210044

出　　处：《大气科学》2014年第1期121-132,共12页Chinese Journal of Atmospheric Sciences

基　　金：国家自然科学基金资助项目41221064;40875052;公益性行业(气象)科研专项GYHY200906017;GYHY201006020;中国气象科学研究院基本科研业务经费2010Z003

摘　　要：利用NCEP／NCAR再分析资料，分析了冬季欧亚中高纬大气低频振荡（LFO）的传播特征及其在年际尺度上与同期欧亚大气背景环流场之间的联系。结果表明，冬季欧亚中高纬LFO以10-30d周期为主，且具有明显向东南方向传播的特征。其经、纬向平均移速分别约为3．4纬度／d和15经度／d。进一步分析发现，冬季欧亚中高纬LFO强度的年际变化与欧亚遥相关型（Eu）密切相关。定义乌拉尔地区的脊和东亚、欧洲西北部的槽比常年弱（强）时，即EU指数小于（大于）零时，为EU负（正）位相。当对流层中上层EU处于负位相时，此时，对流层低层的西伯利亚高压强度减弱，这些因素均导致欧亚地区大尺度经向环流偏弱，环流较为平直，不利于LFO的传播；反之亦然。The propagating characteristics of low-frequency oscillation （LFO） over Eurasian mid-high latitude in boreal winter and its interannual link with the Eurasian background atmospheric circulation are analyzed by using the National Centers for Environment Prediction-National Center for Atmospheric Research （NCEP-NCAR） reanalysis data. The results show 10--30 days dominant periods of low-frequency circulation and clear southeast propagation. The meridional and zonal mean speeds of the 10-30-day LFO are about 3.4 latitudes/d and 15 longitudes/d, respectively. Further analysis shows that the interannual variation of the LFO is closely related to the Eurasian teleconnection pattern （EU）. We define the negative （positive） phase of EU as conditions occurring when the ridge over the Ural area and the troughs over EastAsia and northwestern European are weaker （stronger） than that in an average year such that the EU index is less than （greater than） zero. When the EU at the middle and upper troposphere is in a negative phase, the Siberian high at the low troposphere is weaker. These factors lead to weaker large-scale meridional circulation and dominant zonal circulation over the Eurasian region, which is not conducive to the propagation of the LFO over the Eurasian mid-high latitude or vice versa.

关 键 词：欧亚中高纬 度大气低频振荡 传播特征 欧亚遥相关型 

分 类 号：P461[天文地球—大气科学及气象学]