| Water vapor is an important part of the atmosphere, it is a necessary condition for the formation of rain, which has a great influence on the change of the weather system. It has a close relationship with many natural disasters on earth, but its distribution and variation on the temporal and spatial is quite complex, how to effectively and accurately obtain information of water vapor on disaster prevention and the development of the national economy has important significance. With the rapid development of GPS technology and computer technology, the foundation of GPS water vapor detection becomes a new detection method of water vapor. Compared with the traditional atmospheric water vapor detection method, the water vapor information obtained from the ground GPS has the advantages of high precision, high spatial and temporal resolution, all-weather, not affected by the time and low cost.Studying on the core problems around the atmospheric water vapor content changes, using the principle of GPS Meteorology, a comprehensive study of the CORS station to detect high precision atmospheric precipitation water vapor, GPS slant path water vapor content, three-dimensional space distribution of water vapor and other technical issues. The main research contents are as follows:(1) Based on the observation data collected by Hongkong CORS station, using the GAMIT/GLOBK software to get the PWV of each station. Comparing the GPS/PWV with the results of the King’s Park radiosonde station. Analyzing the effects on the PWV by using different ephemeris from IGS, weighted average temperature models and tropospheric delay models through the experiment.(2) Using the projection method to get SWV, To longitude 114°, latitude 22.20°as the starting point, dividing into a grid at intervals of 0.05 degrees, there are 6 grids on latitude and longitude direction.Setting the height is 850 m, dividing into 10 layers, the mesh number is 360(10 × 6 × 6), which is 3D grid of the Hongkong area. Based on the principle of chromatography, the equation is established. Introducing some common solutions of the equations, using Kalman filtering method to solve the equation group, verifying its feasibility, and drawing the 3D map of water vapor chromatography.(3) The effect of non-uniform layer on the 3D distribution of atmospheric water vapor is analysised. The vertical resolution of 450 m is designed to divide each layer into the atmosphere of lower than 4.5km, divided the atmosphere of 4.5~9km by the vertical resolution of 900 m, and this way total has 15 layers. The results are compared with the previous uniform layer by the vertical resolution of 850 m.This method is more accord with actual situation.(4) By adding the error of ± 50% in the sounding data at 2014. 02.03 as the initial value of the chromatography, the influence of the initial value of chromatography on the Kalman filtering method is discussed. The chromatography results and radiosonde data are consistent with each other. Therefore, the Kalman filtering method is not sensitive to the initial value of the chromatography, loyal to GPS measured data, and to avoid the ill conditioned equation of tomography in some ways. This is its advantage than others. |
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