The Theory And Application Research Of Sensing Water Vapor By Using Local Ground-based GPS Technology

Real-time monitoring of PWV is of great value in researching and predicting disastrous weather because of the important role PWV plays in the power transfer of the weather system. For its advantages in real-time monitoring, high precision, high resolution and low cost, local CORS network has been widely used in the study of local ground-based GPS sensing water vapor, especially in the study of local rainstorm prediction and the evolution mechanism analysis of typhoon. Though regional CORS network has been bettering in our country, the analysis of local ground-based GPS water vapor needs further research because of the regional disparities in the meteorological environment. This paper analyzes the evolution characteristics of GPS/PWV based on Hong Kong local special weather after exploring methods of building local models. The main research contents are as follows:1) The basic theory of sensing water vapor by using local ground-based GPS is represented, focusing on the setup of parameters to Gamit and Bernese high-precision GPS analysis software in sensing water vapor.2) A higher accuracy is achieved by constructing single factor and multi-factor local Tm models based on the sounding data of No.45004 radiosonde station during the recent two years considering that the precision will decrease when Bevis model is applied in local Tm calculation and the timeliness of Xiaoying Wang model.3) An elevation difference correction model about ZTD is built based on the space-time characteristics in Hong Kong; millimeter level forecast accuracy is achieved by using ARIMA model in forecasting short-range and high-precision ZTD of single station; the regional ZTD interpolation model is built based on local CORS network, the interpolated precision of simulation can get millimeter.4) The precision of ZTD calculated by efficient PPP technology in regional CORS network is verified; the feasibility of using PPP technology to analyze localweather is demonstrated; The ZTD of local CORS network is calculated by PPP technology, a ZTD interpolated model is built and the precision of the model can reach the level of the experience models.5) The evolution characteristics of local ground-based GPS water vapor during three typical rainstorms are analyzed and it is concluded that the actual rainfall is irrelevant to the size of GPS/PWV, instead it depends on the GPS/PWV decreasing range and local terrain;6) Regional ground-based GPS/PWV evolution characteristics during the typhoon named “parrot” making landfall over Hong Kong are analyzed, it is concluded that the GPS/PWV peak appears about 120 kilometers from the typhoon and it has not brought any shock to the GPS/PWV during the landing of typhoon;when the typhoon is approaching, the local atmospheric pressure will decrease firstly and then increase, which changes like a V-shaped, during the whole process the atmospheric pressure is of low frequency oscillation, the higher the elevation is, the sooner and the more severe concussion will be.7) The calculation efficiency is greatly improved by designing the assisting calculation program of GPS/PWV through using Visual C++ in view of the shortage of high-precision GPS analysis software and local Tm model can not be directly applied in local ground-based GPS/PWV calculation.