青藏高原春季500hPa纬向风季节内振荡特征及其与我国南方降水的关系  

Oscillation characteristics of 500 hPa zonal winds over the Tibetan Plateau in spring and its association with precipitation in south China

作　　者：杨严[1,2,3] 徐海明[1,2] 

机构地区：[1]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 [2]南京信息工程大学大气科学学院,南京210044 [3]镇江市气象局,镇江212003

出　　处：《南京信息工程大学学报（自然科学版）》2015年第1期58-67,共10页Journal of Nanjing University of Information Science & Technology（Natural Science Edition）

基　　金：公益性行业(气象)科研专项(GYHY201006020);国家自然科学基金(41275094);江苏高校优势学科建设工程(PAPD)项目;江苏省高校"青蓝工程"项目

摘　　要：利用NCEP/NCAR日平均再分析资料及中国753个测站日降水资料,采用带通滤波、小波功率谱、合成分析等方法研究了青藏高原春季500 hPa纬向风季节内振荡特征及其与我国南方降水的关系.结果表明,青藏高原春季500hPa纬向风存在明显的10-30 d季节内振荡特征,该低频振荡主要表现为自西向东和自北向南的传播特征.通过位相合成分析发现,这种季节内振荡对我国南方春季降水有重要影响.当高原500hPa纬向风季节内振荡处于2~3位相时（即高原上盛行西风异常）,对应于我国南方地区春季降水明显偏多;反之,当季节内振荡处于相反位相时（6~7位相,即高原上盛行东风异常）,对应于我国南方春季降水明显偏少.南方春季最大正（负）异常降水的出现滞后于高原季节内振荡的峰值（谷值）位相,其滞后时间为2d.分析结果还表明,高原上空纬向风的季节内振荡活动主要通过中纬度大尺度环流异常对我国南方春季降水产生影响.Using the wavelet power spectrum and composite analysis,the intraseasonal oscillation of 500 h Pa zonal winds in spring over the Tibetan Plateau and its relationship to the precipitation in south China is studied,based on the daily NCEP / NCAR reanalysis and the daily precipitation dataset from 753 stations in China. Results reveal that the 10-30 d oscillation is the dominate period of the 500 h Pa zonal wind variations over the Tibetan Plateau in spring season,characterized by its eastward propagation in zonal and southward propagation in meridional direction.Results also indicate that this 10-30 d intraseasonal oscillation is closely related to the spring precipitation over the south China. As the low-frequency oscillation over the Tibetan Plateau reaches its peak phase（ phase 2-3,i. e.,westerly anomalies over the plateau）,there will be positive precipitation anomalies in south China,and vice versa.In addition,the occurrence of the maximum（ minimum） precipitation anomalies over south China is about 2 days lagged behind the peak（ valley） phase of the intraseasonal oscillation over the plateau. Results further show that the intraseasonal oscillations of 500 h Pa zonal wind over the Tibetan Plateau is highly related to an eastwardpropagating wave train in the mid-high latitudes and through which the oscillation thus affects spring precipitation over south China.

关 键 词：青藏高原 纬向风 振荡 降水 

分 类 号：P461[天文地球—大气科学及气象学]