青藏高原大气热力异常对西风急流的影响  

Influence of atmospheric heat anomaly over the Tibetan Plateau on the westerly jet

作　　者：单幸 周顺武[1] 王美蓉[1] 贲海荣 乔钰[3] SHAN Xing;ZHOU Shunwu;WANG Meirong;BEN Hairong;QIAO Yu(Key Laboratory of Meteorological Disaster, Ministry of Education, Joint International Research Laboratory of Climate and Environment Change, Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters, Joint Center for Data Assimilation Research and Applications, Nanjing University of Information Science & Technology, Nanjing 210044, China;Taizhou Meteorological Bureau, Zhejiang Taizhou 318000, China;Shanxi Meteorological Observatory, Taiyuan 030006, China)

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/气候与环境变化国际合作联合实验室资料同化研究与应用中心,南京210044 [2]台州市气象局,浙江台州318000 [3]山西省气象台,太原030006

出　　处：《气象科学》2019年第2期206-213,共8页Journal of the Meteorological Sciences

基　　金：国家自然科学基金资助项目(41175081;91337218;41605039)

摘　　要：本文基于NCEP/NCAR月平均再分析资料,分析了对流层上层200 hPa纬向西风的时空变化特征,并通过EOF分解得到一个表征西风急流位置的指数(Westerly Jet Position Index,WJPI);同时基于对流层中上层(500~200 hPa)温度纬向偏差,构建了一个描述青藏高原(简称高原)大气热力特征的指标(Plateau Atmosphere Heating Index,PAHI),定量分析了该指数与西风急流位置的关系。结果表明:由冬到夏西风急流轴不断北抬西伸,风速逐渐减小;各季西风急流轴均处于西风变率的小值区,表明各季急流均轴的位置较稳定。各季PAHI与200 hPa纬向风的显著正相关区均分布在高原北侧,即高原PAHI增强时,其北侧西风增强,南侧西风减弱,对流层上层西风急流北移;各季WJPI与PAHI之间均存在显著相关,表明PAHI异常对西风急流位置的变化有重要作用。Based on the NCEP/NCAR reanalysis dataset from 1979 to 2014, the temporal and spatial characteristics of the 200 hPa zonal winds were analyzed. Through the EOF decomposition, an index presenting the Westerly Jet Position Index(WJPI) was obtained, and meanwhile the index describing the Atmospheric Heating over the Tibetan Plateau (PAHI) was also constructed based on the temperature zonal deviation at the upper-middle layer (500-200 hPa) of the troposphere. The relationship between PAHI and the westerly jet position was also quantitatively analyzed. Results show that the westerly jet axis gradually moves northward and westward from winter to summer, with decreasing wind speed. Westerly jet axes are always located in the small value area of the westerly variability in all seasons, suggesting that the jet position is relatively stable in every season. The significant positive correlation areas between PAHI and 200 hPa zonal winds in each season are located in the northern TP, indicating that strong PAHI gives rise to the strengthened westerly over the northern TP and the weakened westerly over the southern TP, and then the westerly jet in the upper tropospheric moves northward. The significant correlations between WJPI and PAHI exist in four seasons, which further demonstrates that PAHI anomaly play an important role in the position changes of the westerly jet.

关 键 词：青藏高原 西风急流 急流位置 大气热力指数 

分 类 号：P442[天文地球—大气科学及气象学]