Fusion Analysis Of All-time Precipitable Water Vapor Based On Sun Photometer And Raman Lidar

Precipitable water vapor is an important part of atmosphere and one of the most important factors in meteorology and climatology.As a kind of gas with rapid spatial and temporal variations,real-time continuous detection of atmospheric water vapor has significant effect and value for the study of cloud formation,precipitation,water cycle and haze generation and elimination process.In this paper,the atmospheric water vapor content throughout the day has taken as the research goal to study the distribution and variation characteristics of it in a large range by using the fusion analysis of sun photometer and lidar.In this paper,the retrieve and research of atmosph eric water vapor content based on sun photometer was carried out,and the diurnal,monthly,seasonal and annual trends of aerosol optical parameters such as Aerosol optical depth,Angstrom exponent and Turbidity exponent in Xi’an area from 2015 to 2017 were statistically analyzed.The total column water vapor content was obtained by using the solar radiation data of the sun photometer 940 nm channel,and the monthly average variation range of the local water vapor content in Xi’an area is from 0.1 to 2.7 cm showing the trend of high value in summer and low value in winter.Then,all-time water vapor detection and retrieve based on raman lidar was obtained,and the effective detection of atmospheric water vapor below 3 km during the day has realized,and then the all-time lidar detection of atmospheric water vapor was obtained.Combined with the advantages of sun photometer in daytime detection,the fusion analysis of the total column water vapor content obtained by sun photometer and the water vapor content in the boundary layer obtained by lidar was discussed through some typical detection examples.The results of data analysis show that the two have the same changing trend,and the positive correlation coefficient is more than 0.7,which indicates that the water vapor content in the bottom layer of the atmosphere can accurately reflect the changing trend of the water vapor content in the whole layer.In order to obtain the distribution of atmospheric water vapor content iii a large range further,this paper aims at the advantages and disadvantages of lidar,sun photometer and mode data to study splicing method of atmospheric water vapor profile based on raman lidar and mode in large range.And the water vapor profile splicing of lidar and NCEP or WRF mode has realized.The high precision water vapor mixing ratio profile in the large height ran ge of near ground to 20 km was obtained.The continuous THI diagram of water vapor temporal and spatial variation showed the continuity of atmospheric water vapor data and clearly showed the change o.f atmospheric water vapor layer.Finally,the water vapor content obtained after splicing profile has been compared and analyzed with that of synchronous sun photometer.The results show that the trend of the two is the same,and there is a strong positive correlation,and the correlation coefficient is more than 0.8.The feasibility of the fusion method of lidar combined with sun photometer and mode data has verified,which provides the corresponding technical support for the study of all-time atmospheric water vapor content in a large range.