Application Analysis Of Ground-based GNSS Water Vapor Inversion In Yunnan Area

The water vapor in the atmosphere is only about 3%,but water vapor plays a very important role in meteorological forecasting and atmospheric scientific research.The accumulation and release of water vapor are directl y related to changes in the weather s ystem,and some catastrophic weather can be forecast and monitored based on changes in water vapor.However,the distribution of water vapor in the atmosphere is extremel y irregular,and the change of water vapor itself is very complicated.Therefore,water vapor has become an important factor in accuratel y asse ssing atmospheric changes and forecasting severe weather.In recent years,phenomena such as global extreme weather and meteorological disasters have occurred from time to time.Most disasters such as urban waterlogging,heavy rains,landslides,etc.are closel y related to precipitation,and precipitation is directl y rel ated to atmospheric water vapor.Rainstorms,droughts,frosts and other phenomena occur frequentl y in most parts of Yunnan,and there are obvious differences in precipitation and climate change in different regions,which are importantl y related to the topography and geography of Yunnan.This article uses the data of continuousl y o perating reference stations in Yunnan to invert water vapor in Yunnan,and anal yzes the relationship between precipitable water vapor and the temporal and spatial changes of climate and precipitation in parts of Yunnan.It verifies the important role of ground-based GNSS in precipitation prediction and climate change monitoring.The main content and conclusions are a s follows:(1)Establishment of regional weighted average temperature model in Yunnan.By collating the observation data of the sounding stations in Yunnan for 8 years,and using the method of regression anal ysis,a single station model and a regional mod el of the weighted mean temperature in Yunnan are obtained.The weighted average temperature of each station is taken as the most probable value by numerical integration method to check the accuracy of the established single-station model and regional model.The experimental results show that the accuracy of the single-station model and the regional model established in the experimental area is higher than that of the traditional empirical model,which indicates that the regional model established in Yunnan area is reasonable and effective.(2)Anal ysis of influencing factors of ground-based GNSS inversion PWV.The absolute zenith delay(ZTD)of some regions in Yunnan was obtained by using GNSS data solution software to solve CORS stations in Yunnan.The influenc e of several external factors(auxiliary stations,cut-off height Angle,tropospheric delay correction model,mapping function,satellite ephemeris)on the accuracy of water vapor inversion is anal yzed.Finall y,based on the experimental results,a solution strategy suitable for GNSS inversion of water vapor content in Yunnan region is given.(3)Three-dimensional-water vapor chrom atograph y experiment in Yunnan.C ombined with the regional wei ghted average temperature model and the calcul ation strategy,the PWV time series of Yunnan region was obtained.The SWV of atmospheric moisture content in oblique path over the station was calculate d by the back projection method.According to the principle of water vapor ch romatography,the results of the southwest region w ere obtained by taking the southwest Yunnan as the experimental area.(4)Application of ground-based GNSS water vapor detection in Yunnan.Co mbined with GNSS water vapor inversion technology and m eteorological data anal ysis methods,the actual precipitation and water vapor distribution in Yunn an were anal yzed,and the application of PWV in regional climate change wasanal yzed based on the relationship between PWV and actual precipitation.Theregional rainfall prediction model is established by combining neur al networkwith PWV.The results show that the prediction accuracy of the model is 68%,the false alarm rate is 4%,and the false alarm rate is 28%.The experiment f urther confirmed the great potential of the ground-based GNSS water vapor de tection technolog y i n the prediction of climate change and precipitation in Yu nnan.