|Budget Amount *help
¥7,700,000 (Direct Cost : ¥7,700,000)
Fiscal Year 1999 : ¥2,800,000 (Direct Cost : ¥2,800,000)
Fiscal Year 1998 : ¥4,900,000 (Direct Cost : ¥4,900,000)
The purpose of the study is to understand the subsurface water cycle as a part of hydrological cycle at a synthetic stand point of view. Study sites are Shimousa upland, Chiba prefecture, Japan, and North China Plain, China. The former is the urbanized region located near the Tokyo Metropolitan Area, and the latter is the region that the water problem due to over extraction of groundwater is apprehensive for the world food security.
Different methods including field investigation, computer modelling, satellite remote sensing, etc., were applied to the areas with different spatial scales. The following three targets were investigated in the study term.
1)Understanding of hydrological cycle in the experimental watershed or in the plot scale
Field observation on the water movement cycle was carried out in the Quaternary upland where subsurface water cycle is the dominant processes of hydrological. Typical valley in Shimosa upland was selected as extensive observation basin, and the hydrologi
cal data over one year were collected and currently analyzed. Feasibility of satellite remote sensing was examined to estimate areal evapotranspiration. Close relationship between evapotranspiration and spectral brightness measured by satellite was found, and it enables the satellite estimate of evapotranspiration over extensive area.
2)Integration of hydrological data by geographic information systems(GISs)
River water quality data by Chiba Prefectural Office were re-constructed as database on the GISs. Typical urban watershed, Mama-gawa basin, was selected and various spatial information, including present and past landuse, the indices of human activities, etc., are stored on the GISs. These spatial data were used as boundary condition of hydrological model to estimate the effect of human activity to the hydrological cycle.
3)Water budget and hydrological processes in North China Plain, China
Field observation network was constructed as China-Japan joint research project. The data on flux, water chemistry, was obtained over one year. Satellite monitoring on vegetation and hydrological state variables were continuing to expand plot scale measurement to wide area. Less