Study Of Atmospheric Water Vapor Distribution And Change Over Tibetan Plateau And Around Area

The thermal and dynamical effect of Tibet Plateau is very important for regional and global weather and climate change. Studying atmospheric water vapor distribution and change over Tibetan Plateau and around area is an important way to realize the thermal and dynamical effect of Tibet Plateau for regional and global weather and climate change, to realize regional water cycle over Tibet Plateau. Foretime, many studies for atmospheric water vapor distribution and change over Tibetan Plateau were made, but the results based on the data and observations whose resolution and precision is low were not satisfactory because of low spacial resolution and low precision. In this paper, study of atmospheric water vapor change and distribution over Tibet Plateau and around area is based synthetically on GPS, MODIS remote sensing data and ground meteorological sites observations data.Firstly, the GPS data in Naqu, Gaize, Deqn, Tengchong, Mengzi and Simao are processed, the change of remote sensing water vapor using six ground GPS receivers in Tibet Plateau and Yunan province are analyzed, the results based on GPS with those based on the radiosonde data are compared, and the relationships between the amount of atmospheric water vapor and the ground vapor pressure, ground temperature and precipitation are studied. It shows that the annual amount of atmospheric water vapor is about 0.2~2.0cm over Tibet Plateau and 0.5~4.5cm in Yunan province. It shows that a coincidence with rmse: 0.152cm dose exist between the results based on GPS and those based on the radiosonde data on Tibet Plateau and a coincidence with rmse: about 0.3 cm in Yunnan. The results based on the GPS observations agrees well with those based on the radiosondes observations over Tibet Plateau and so it dose in Yuan province. It also shows that a negative correlation exists between the value of atmospheric water vapor and ground temperature in Gaize and Naqu, especially the negative correlation coefficient becomes larger in July. Precipitation is well related with the change of atmospheric water vapor and an abrupt increase of regional precipitable water vapor is companied with precipitation, although the value of integrated precipitable water dose not correspond tothe amount of the precipitation. Also, there is a good relationship between the amount of atmospheric water vapor (PW) and ground vapor pressure (e).After analyzing the relationship between the amount of atmospheric water vapor (PW) and ground vapor pressure (e), precipitable water vapor retrieved by GPS with those based on numerical models are compared in order to assess precision of the results based on numerical models. And atmospheric water vapor distribution and change are studied synthetically based on GPS, radiosonde and other ground weather observations data over Tibet Plateau and around area.Because the spacial resolution of ground observations data is low, MODIS data are used with GPS data to study atmospheric water vapor distribution and change over Tibetan Plateau and around area. The values of atmospheric water vapor retrieved by GPS are compared with those retrieved by MODIS to validate the result based on the MODIS data. It shows that GPS precipitable water vapor is much lower than those retrieved by MODIS. And then, Atmospheric water vapor retrieved by MODIS is corrected based on relationship between precipitable water vapor by GPS and those by MODIS.It shows that it is moisture in the southeast part of Tibet Plateau and it is dry in the northwest part. The isolines of amount of precipitable water vapor are dense and the grads value of integrated precipitable water in the direction from southeast to northwest is very large over the southeast part of Tibet Plateau. There are two centers of high amount of water vapor, one is over grand canyon of Brahmaputra River southeast of Tibet Plateau, the other is over Sichuan Basin east of Tibet Plateau. It is also high moisture over the area around two centers. The grand canyons of rivers southeast Tibet Plateau are the important accesses through which a...