Remote Sensing Precipitable Water Vapor By Ground-based GPS And Its Meteorological Application In North China

In this thesis, four key problems of veracity and integrity in remote sensing precipitable water vapor are studied in North China. The results show:(1) In order to improve the lacking and miscalculating rate in ground-based GPS data, programs are programming to calculate precipitable water vapor according to the principle of ground-based GPS/MET.(2) Some different methods are introduced and compared in North China, the following results indicate that there is a systematic error in these areas by using Bevis empirical formula. Some regression equations of the weighted mean temperature based on single factor or multi-factor are given in North China. It is helpful to meet the need of remote sensing real-time and high precise precipitable water vapor by ground-based GPS.(3) The corresponding precipitable water vapor is calculated based on sounding and GPS data in North China, the relationship between precipitable water vapor and surface observational data are analyzed. Different empirical formulas are established under different classifications by using regression method. As the result, the formula considering sky condition is the best and can be used as the replacement of estimating precipitable water vapor besides radiosonde method and GPS technology.(4) Comparing GPS technology with radiosonde method in calculating precipitable water vapor, ground-based GPS is an important way with high precise and temporal distribution.In addition, on the base of the above analysis, the temporal and spatial distribution features of precipitable water vapor in GPS are analyzed, and the relation between precipitable water vapor and real precipitation are also studied in Shijiazhuang, Qinhuangdao and Zhangjiakou city. With the analysis of precipitable water vapor in convective precipitation produced in the laminose cloud, steady precipitation in the layer cloud, and the heavy rain in the laminose and layer mixed cloud, some valuable conclusions are put forward in this thesis, and it provides a reference for the short range forecasting and nowcasting.