GMS－5水汽图象所揭示的青藏高原地区对流层上部水汽分布特征

UPPER TROPOSPHERIC MOISTURE DISTRIBUTION OVER THE TIBETAN PLATEAU AS REVEALED FROM GMS-5 WATER VAPOUR IMAGES

该文利用１９９５年６月中旬至７月初ＧＭＳ－５水汽图象，对青藏高原地区对流层上部水汽分布进行了初步分析．发现高原地区对流层上部水汽的汇集主要通过以下４种方式进行：①水汽从高原东南方的雅鲁藏布江河谷等地进入高原，是主要路径；②从西南方越过喜马拉雅山进入高原；③从帕米尔及其以北地区漂过塔里木盆地后进入高原；④对流活动可以引起水汽在高原上空积聚．从多时相平均水汽图象上反映出高原上西北干、东南湿的水汽分布特征，并初步讨论了水汽图象所揭示的在高原生成的系统对我国东部天气的影响．

With GMS-5 Water vapour images the upper tropospheric moisture distribution over the Tibetan Plateau is analyzed.It is indicated that water vapour accumulation over the Tibetan Plateau is mainly in one of the following ways:(a)Climbing up through Yarlung Zangbo River and Brahmaputra River valley;(b)Acrossing Himalayas;(c)Drifted from upstream Pamir through Tarim Basin;(d)Local ascending motion. Mean moisture pattern reveals a moisture region in the southeast part and a dry region in the northwest part of the Plateau.The boundary between the two regions is along the mountain ranges in the middle of the Plateau.This boundary is the place where new systems is triggered,which may cause regional precipitation later in the eastern part of China in July and August of 1995.Of seven major regional precipitation events in Northern China,five events were related with system triggered in the Tibetan Plateau.It is also shown that water vapour images can reveal the genesis of systems over the Plateau which are favorable to the improvement of regional,precipitation forecast for the eastern part of China.