Analysis of Precipitable Water Vapor Source Distribution and Its Seasonal Variation Characteristics over Tibetan Plateau and Its Surroundings
青藏高原及周边地区大气水汽资源分布和季节变化特征分析

Based on the ground GPS,MODIS remote sensing data and NCEP data grid reanalysis data on the Tibetan Plateau and its surroundings in 2001,precipitable water vapor distribution and its seasonal variation characteristics are studied over these areas.The result shows that precipitable water vapor column changes between 3 and 30mm in the southeastern part,and between 2 and 20mm in other parts of the Tibetan Plateau.So it is moist in the southeastern part and dry in the northwestern part.There are two high water vapor centers throughout the year, one is over the Grand Canyon of the Yarlung Zangbo River southeast of the Plateau,the other is over Sichuan Basin east of the Plateau.There are also two moisture centers over the surrounding areas. The Grand Canyon is an important access through which a great deal of water vapor reaches the interior of the Plateau.With seasons alternating,the transportation of water vapor from the Grand Canyon changes obviously.Reasonably,a moisture region in the southeastern part and a dry region in the northwestern part of the Plateau are determined by its geographical latitude and the altitude.However precipitable water vapor distribution and its seasonal variations over the Plateau and its adjacent areas are mainly determined by general circulation of atmosphere. Moreover,the transportation of water vapor to the interior of the Plateau by general circulation is different during different seasons,and the transportion intensity of water vapor to different parts of the Plateau is different as well.