| The proportion of water vapor in the whole atmosphere is very small,but water vapor is the most violent part of the atmosphere changing with time.The weather change is mainly caused by the drastic change of water vapor in time and space.Therefore,it is very important to obtain the distribution of water vapor with time and space for weather forecast and prevention of disastrous weather.Ground-based GPS inversion of water vapor is a new method to detect atmospheric water vapor,which makes up for many shortcomings of the traditional technology.In this paper,17 CORS stations of the Hong Kong satellite positioning reference network(Sat Ref)and 4 international GNSS stations are introduced,which is the data of BJFS,PIMO,LHAZ and WUHN respectively,jointly carry out the water vapor inversion and solution experiment of GPS tomographic three-dimensional atmospheric water vapor.Based on the weather data of Hong Kong jingshibai sounding station(45004),the water vapor calculated is the true value,and the accuracy of the results is compared and analyzed.The main contents of the experiment are as follows:1.Based on the meteorological data of Hong Kong's jingshibai sounding station(45004)from 2014 to may 2018,a weighted average temperature model_mT for Hong Kong's atmosphere in May is obtained.The results show that the weighted average temperature T_m error of May calculated by the localized model is basically within 3.4K,and the precipitable water error is within 1mm.2.In this paper,the data of 17 stations in the Hong Kong reference station network(satref)and the data of BJFS,PIMO,LHAZ and WUHN,four auxiliary international GNSS service stations in the surrounding area,are used to carry out the atmospheric water vapor inversion.The results of the atmospheric precipitable water calculated by the HKSC inversion of the station and the precipitable water calculated by the data of the sounding meteorological station are in good contrast,with an average deviation of 0.82mm.The root mean square error is 1.04mm and their correlation coefficient is 93%.The analysis of a precipitation process in Hong Kong shows that the distribution of atmospheric precipitable water is basically consistent with that in Hong Kong,which proves that the atmospheric precipitable water quantity retrieved by GPS can reliably and accurately reflect the state of water vapor in the atmosphere.3.The three-dimensional distribution map and time series map of atmospheric water vapor obtained from ground-based GPS tomographic inversion are compared to obtain the distribution of atmospheric water vapor with time and space under rainstorm weather conditions.Combined with GPS three-dimensional tomographic water vapor field,the change process of small-scale water vapor field in the process of strong convection(rainstorm)is given.In the vertical direction of the tomographic grid,the value of atmospheric water vapor density is inversely proportional to the tomographic height,that is,the higher the height,the smaller the value of atmospheric water vapor density.The average value of water vapor density in each layer of the chromatography grid below 3km is about12.56g/m~3,accounting for 69.70%of the total water vapor in each layer;in the horizontal direction,the distribution difference of water vapor in each layer in the horizontal direction will not decrease with the increase of height.The difference of water vapor distribution in1-2km,2-3km and 8-9km layers is the most obvious,which is 0.87g/m~3,0.94g/m~3 and0.87g/m~3 respectively. |
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