Estimate of Integrated Water Vapor using data from gauge gauge GNSS stations for application in tropospheric on Natal and Mossoró cities, in Rio Grande do Norte State, Brazil.
GNSS; ZTD; IWV; Pluviometry; Nowcasting
The GNSS signal analysis (Global Navigation Satellite System) issued by satellites has been widely used in the field of geodynamics and geodesy, as a sensor for speed measurements and displacement of tectonic plates and the representation of the shape and the Earth's surface. However, the satellite signal is delayed as it crosses the earth's atmosphere, specifically in two of its layers: (a) the ionospheric layer, where the signal is delayed by ionized atoms present in this region, and (b) the tropospheric layer, due to the presence of water vapor, and is strongly related to the amount of water vapor precipitable present in that region. This work presents data analysis of GNSS signals obtained from surface gauge stations, aiming applications related to the amount of water vapor in the troposphere. Data from GNSS signals were obtained from IBGE (Instituto Brasileiro de Geografia e Estatística) through RBMC web (Rede Brasileira de Monitoramento Continuo dos Sistemas GNSS). Data processing was performed using the GIPSY software, from JPL-NASA (Jet Propulsion Laboratory), which processes the observed data from satellites and provides ZTD values (Zenithal Tropospheric Delay). Knowing the temperature and pressure on the antenna, one can estimate IWV (Integrated Water Vapor), which can be related to the local pluviometry. Applications were made on the cities of Natal and Mossoró, in the Rio Grande do Norte State, and correlations were made between the variables from the time series obtained for the ZTD parameters, IWV and Pluviometry, using statistical analysis from the R-software. The use of GNSS signals has been used as a tool for NWP, numerical weather prediction, using the IWV parameter as input for applications in Nowcasting models.