西藏高原汛期水汽输送特征与降水异常  

Features of Water Vapor Transfer in Rainy Season and Their Relations to Rainfall Anomalies over Tibetan Plateau

作　　者：林志强 唐叔乙 何晓红 德庆 文胜军 

机构地区：[1]西藏自治区气象台,拉萨850000

出　　处：《气象》2011年第8期984-990,共7页Meteorological Monthly

基　　金：国家自然科学基金(40865008)资助

摘　　要：利用1979—2006年NCEP/NCAR再分析资料计算垂直积分的整层水汽输送通量及水汽通量散度,分析西藏高原汛期5—9月水汽输送特征。结果表明:两藏高原汛期主要有两条水汽输送带,印度季风输送带和中纬度西风输送带;印度季风对汛期水汽输送起着决定性的作用,决定高原汛期开始时间和雨带的推进,水汽通量向北输送达到30 kg·m^(-1)·s^(-1)时,该经度上的测站将从南到北逐渐进入汛期;在水汽的空间分布上,高原南部边缘的3个水汽输送散度场中心恰好对应着高原的水汽输送通道,其形成与西藏高原的地形直接相关;西藏高原汛期降水主要可以分为3种雨型:全区型、东西型和南北型,并分别对应着不同的水汽输送异常:全区型时索马里越赤道急流水汽输送异常较强,高原区为水汽辐合区;东西型时西藏东南部为东北向输送异常,东南部水汽供应较常年偏弱;南北型时东南部水汽输送充足而错那以西地区水汽输送不足。The features of water vapor transfer in rainy season（May to September） are studied based on the NCEP/NCAR reanalysis data that are used to compute the vertically integrated water vapor flux and water vapor flux divergence from 1979 to 2006.The results have shown that the main features of the water vapor transfer over the Tibetan Plateau are one monsoon,two water vapor transfer channels and three important water vapor sources.The India summer monsoon which dominates the start time of plateau＇s rainy season and the motion rainfall bands,plays a decisive role in the Tibetan Plateau＇s rainy season water vapor transfer.The weather stations near the longitude that northern water vapor flux reached 30 kg·m^（-1）·s^（-1） would gradually come into the rainy season.The three centers of water vapor transfer divergence field in the southern border of the Tibetan Plateau are just corresponding to the plateau＇s water transfer channel, and its formation is related to the terrain of Tibetan Plateau.Rainfall anomalies in Tibetan rainy season can be mainly divided into three raining patterns,they are Whole Region Pattern,East-West Pattern and North-South Pattern.These patterns are related to different water vapor transfer anomalies.For example, when it is in the whole Region Pattern the anomaly of the Somali cross-equatorial flow zone is stronger.

关 键 词：水汽输送 西藏高原 汛期 降水异常 

分 类 号：P457.6[天文地球—大气科学及气象学]