| The atmospheric water vapor content can also be called PWV(Precipitable Water Vapor),which is defined as the amount of atmospheric water vapor contained in the unit area from the ground to the high air column to the ground precipitation,which is one of the necessary conditions for the generation of precipitation.Although its content in the atmosphere is not high,it plays a crucial role in weather forecasting,micrometeorology,global climate change and so on.Therefore,how to accurately measure the atmospheric water vapor' content and its temporal and spatial distribution is of great significance to the study of climate change.How to detect the real-time data of high precision water vapor has become a problem that has been discussed and solved by the academic circle.In this paper,Hongkong area is taken as the research area to explore the distribution of water vapor in Hongkong area.The advantages and disadvantages of various methods of water vapor detection are compared and studied.The GPS data of the foundation is fused with other data to generate high precision,high temporal resolution and strong spatial continuity of atmospheric water vapor data so as to facilitate the study of small and medium scale climate.In this paper,the atmospheric water vapor content is mainly studied.Two important process parameters are the zenith wet delay and the atmospheric weighted average temperature.The main processes and conclusions of this paper are as follows:(1)in this paper,GAMIT software is used to build an integrated GPS inverse dry delay integration process,and the automated batch processing based on shell language is realized in the Linux system.The automation batch processing and manual intervention are combined to improve the working efficiency,and the total delay of the zenith is finally obtained.Then compared the precision of three kinds of zenith dry delay universal model(Saastamoinent model,Hopfiled model,Black model)in the Hongkong area,and finally select the Hopfiled model to calculate the zenith dry delay.Finally,with zenith total delay minus the zenith delay,important process parameters,zenith wet delay,are obtained.(2)in the study of another important process parameter atmospheric weighted mean temperature(Tm),this paper makes a comparison and analysis of various existing models.It is found that the precision of building Tm local model is the highest,but it is very difficult to construct a new local model in different regions of China.Therefore,this paper is based on the 83 national sounding stations,the root of this paper.According to the distribution law of Tm local model coefficient,China is divided into 5 regions,the Tm model is established respectively,and the model is optimized in season,and the air weighted average temperature model of different seasons in different seasons in different seasons in China is established.Comparing the model built in this paper with the existing models,we find that this model has higher accuracy and wider application scope.It effectively improves the efficiency and accuracy of retrieving water vapor from ground-based GPS.(3)using the two process parameters of the zenith wet delay and the weighted average temperature of the atmosphere,the water vapor in Hongkong area is finally obtained through a series of conversion,and the foundation GPS PWV is compared with the sounding PWV,and the accuracy is found to be equivalent to the sounding data,and the time resolution and spatial resolution are much higher than that of the sounding data.The study of water vapor by empty data can provide real-time and accurate water vapor data.(4)the spatial resolution of MOD05 data is high.It can continuously observe the spatial distribution of water vapor over a large range,but the accuracy is low.In this paper,the GPS data and MOD05 data are fused,and the high precision,high spatial resolution and continuous water vapor data are obtained,which lays the foundation for the later research. |
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