The use of terrestrial networks for the continuous monitoring of Global Positioning System (GPS) signals in the quantification of IWV (Integrated Water Vapor in the atmospheric column) is a multidisciplinary application with great potential for the monitoring of atmospheric water vapor concentration, which presents good perspectives for several studies related to the atmospheric sciences (Sapucci et al., 2007).
A relation between the values of and the amount of atmospheric water vapor (IWV) present at the time of GPS observations is a function of the mean tropospheric temperature (). This relation can be expressed by the following equation (Bevis et al., 1992):
where is the specific constant for water vapor, and are the atmospheric refractive constants whose values were determined experimentally (Bevis et al., 1994). The values of can be approximated from surface temperature measurements (Bevis et al., 1992). For regions of the Brazilian territory an adequate modeling that relates the values of with data obtained at the surface was developed using 90,000 radiosondes (Sapucci et al., 2004).
Doc. Nilson Sant'Anna - Coordination