Earth Planets Space, Vol. 52 (No. 11), pp. 927-933, 2000
Hiromu Seko1, Seiichi Shimada2, Hajime Nakamura1, and Teruyuki Kato1
1Meteorological Research Institute, 1-1 Nagamine, Tsukuba, Ibaraki 305-0052, Japan
2National Research Institute for Science Disaster Prevention Institute, 3-1 Tennodai, Tsukuba 305-0006, Ibaraki, Japan
(Received December 31, 1999; Revised July 26, 2000; Accepted September 7, 2000)
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.