Study And Application Of Estimating Atmospheric Water Vapol By Ground-based GPS Technology

The technology of estimating atmospheric water vapor based on GPS is a new a new means of detecting water vapor,which can make up for the disadvantages of conventional means.The technology of estimating atmospheric water vapor based on GPS can provide high precision,large capacity,real time information of water vapor.The purpose of the study is to further improve the accuracy and practicalities of GPS water vapor,and explore the ability of detecting atmosphericwater vapor,so that it can serve the meteorological service better.This study discusses some issues about the computations of tropospheric delay,these issues include the choice and setting of calculated parameters.The results indicate that it is very possible for common stationto to use double difference to obtain the initial coordinate,the calculated results of tropospheric delay with precipitable precise ephemeris and post-processing precise ephemeris are basically in line,an ideal result of tropospheric delay can be obtained with the LC dummy observation of dual-frequency combination;Based on actually surveyed data,three different kinds of hydrospher delay models are analyzed,the result indicate that the accuracy of surface pressure has a major impact on hydrospher delay;According to the theory of linear regression and the radiosonde data of Kunming during the period of October to December 2008,the calculation model of the mean vapor pressure-weighted tempereature of the atmosphere(Tm) in kunming areas is established,then the model is applied to estimate Tm and GPS precipitable water vapor,in the comparison between results of Kunming Tm model and Bevis Tm model in Kunming station,the Tm and GPS precipitable water vapor of Kunming Tm model and radiosonde observations are closer than the Tm and GPS precipitable water vapor of Bevis Tm model,this proves the reliability and usability of GPS precipitable water vapor based on Kunming Tm model;Finally,according to the observational data of Nineteen GPS stations during the period of February,May,August,November 2008 in the East Asian region,the GPS precipitable water vapor is inverted,in Shanghai station,the root mean square of difference between GPS precipitable water vapor and radiosonde precipitable water vapor is 4.39mm,the standard deviation is 4.31mm,the correlation coefficient between GPS precipitable water vapor and radiosonde precipitable water vapor is 0.9741,this proves the reliability of the inversion results,then based on the GPS precipitable water vapor of Nineteen stations and the Interpolation method,the contour maps of distribution of GPS water vapor in the the East Asian region are plotted,based on the atmospheric circulation in the the East Asian,the GPS water vapor is basically in accordance with the regularity of water vapor of the the East Asian.