Analysis of Precipitable Water Vapor over South America

C. BIANCHI; J. EPELOA; L. MENDOZA; L. FERNÁNDEZ; P. NATALI; A. MEZA; J. MOIRANO

Praga

Congreso; 26th IUGG General Assembly; 2015

International Union of Geodesy and Geophysics

The Precipitable Water Vapor (PWV) is one of the key variables needed tomodel the spatial and temporal behavior of tropospheric phenomena. While regular radio-soundings are poorly distributed over South America a constantly growing network of continuously operating geodetic GlobalPositioning System (GPS) stations is being deployed over the continent for the last 30 years. We compare PWV estimation from GPS with respect to PWV from radio-soundings and the respective values from ERA Interim for a set of stations in South America during 2008 to 2013. The analysis involves stations in different climate types according the Köppen and Geiger classification. The comparison displays an overall agreement on the millimeter level between PWV coming from radio sounding and from GPS processing. The differences show a normal distribution with a mean values ranging from -0.3 to 0.5 mm. and a correlation higher than 0.9. The discrepancy between PWV from ERA Interim and the respective values from GPS is mainly due to the difference in heights where the values are computed. We can conclude that reliable PWV values can be recovered from a regional continuously operating geodetic GPS network with accurate pressure and temperature surface information available nearby.