Detection of Spatiotemporal Changes of Water Vapor based on Large-scale BDS Reference Stations in China Area

<p>China has built  national BDS reference stations (≥210 ) covering the entire territory and has been operating continuously for more than 3 years. In 2020, BDS  satellite navigation and positioning system will be fully built and provide global services, providing a good source of data for the use of ground-based BDS observations for water vapor detection and analysis. The author used national BDS reference stations observation data which covered China area  in 2019, combined with sounding observation data, to detect and analyze the temporal and spatial changes of water vapor , and given preliminary analysis results of the  water vapor detection performance and accuracy based on BDS observation . The results show that the detection results of atmospheric precipitation between BDS and sounding system are more consistent, which can reflect the change of atmospheric precipitation.  The system errors and standard deviations of the calculation results which based on  the BDS  observations and the sounding observations are relatively large, which may be related to orbit model and  the system stability of BDS needs to be improved.</p>

THE FOUNDATION GPS WATER VAPOR INVERSION AND ITS APPLICATION RESEARCH

Using GPS technology to retrieve atmospheric water vapor is a new water vapor detection method, which can effectively compensate for the shortcomings of conventional water vapor detection methods, to provide high-precision, large-capacity, near real-time water vapor information. In-depth study of ground-based GPS detection of atmospheric water vapor technology aims to further improve the accuracy and practicability of GPS inversion of water vapor and to explore its ability to detect atmospheric water vapor information to better serve the meteorological services. In this paper, the influence of the setting parameters of initial station coordinates, satellite ephemeris and solution observation on the total delay accuracy of the tropospheric zenith is discussed based on the observed data. In this paper, the observations obtained from the observation network consisting of 8 IGS stations in China in June 2013 are used to inverse the water vapor data of the 8 stations. The data of Wuhan station is further selected and compared with the data of Nanhu Sounding Station in Wuhan The error between the two data was between -6mm-6mm, and the trend of the two was almost the same, the correlation reached 95.8 %. The experimental results also verify the reliability of ground-based GPS inversion of water vapor technology.

FABRICAÇÃO E CARACTERIZAÇÃO DE FILMES FINOS DE OC8OC8-PPV APLICADOS EM DISPOSITIVOS SENSORES DE UMIDADE

Thin films of poly (p-phenylene vinylene) derivatives can be used in several devices, such among them sensors and photovoltaics, mainly because of the ease of synthesis and solubility in organic solvents. Within this context, thin films of poly(2,5-dihexyloxy-1,4-phenylenevinylene) studied were deposited by Langmuir-Blodgett and Langmuir-Schaefer techniques. To this end, solutions of the pristine polymer and its mixture with stearic acid in chloroform were used. These films were deposited onto gold interdigitated electrodes and characterized in direct current, obtaining current versus applied voltage measurements for analysis of the films intrinsic conductivity and electrical current versus time for sensory characterization of the samples when they were under the continuous flow of water vapor. These devices revealed water vapor detection and reversibility in the process.

Two-year operation of the lidar1200: from fine-scale tropospheric structures to lower stratospheric water vapor detection

The 2-year lidar water vapor database (November 2013 - October 2015) of the Maïdo Observatory (Reunion Island / 21°S,55.5°E) is now processed. The performances of the lidar in providing accurate vertical structures are shown to be good. The ability to measure quantities of a few ppmv in the lower stratosphere is demonstrated (based on Cryogenic Frost point Hygrometer sonde/lidar profiles comparisons) for a 48-hour integration time period, up to 22 km (with a vertical resolution of 1.3 km).