Three-dimensional distribution of water vapor estimated from tropospheric delay of GPS data in a mesoscale precipitation system of the Baiu front

Abstract

Three-dimensional distributions of water vapor in a mesoscale precipitation system, which developed on 7 July 1996 in the Baiu front, were estimated directly from the GPS data of ‘GPS Earth Observation Network’ (GEONET) of the Geographical Survey Institute. In estimating the three-dimensional distribution of water vapor from the GPS data, we used the tropospheric delays along each path from GPS satellites to GPS receivers on the ground. The result showed that the moist air extended up to the height of 6 km in the precipitation region in the early stage of the precipitation system and that a dry air intruded into the precipitation system from the northwest in the middle-level (from 3 km to 5 km altitude) in the later stage. This dry air intrusion in the middle-level was supported by numerical simulations.