Study on the integrated perception of subsurface hydrological cycle and its anthropogenic change

本研究的目的是从综合的角度理解地下水循环作为水文循环的一部分。考察点是日本千叶县下泽高地和中国平原北部的中国。前者是东京都市区附近的都市化地区，后者是地下水超采对世界粮食安全构成威胁的地区，不同空间尺度的区域分别采用了实地调查、计算机模拟、卫星遥感等方法。1)在实验流域或小区尺度上了解水文循环在第四纪旱地进行了水分运动循环的野外观测，那里的地下水循环是主要的水文过程。选取下部丘陵典型河谷为大面积观测流域，水文…收集了一年多的CAL数据，并进行了分析。探讨了卫星遥感估测区域蒸散量的可行性。2)利用地理信息系统(GISS)集成水文数据千叶县办事处的河流水质数据被重建为GISS上的数据库。选取了典型的城市流域--玛玛嘎瓦流域，在GISS上存储了各种空间信息，包括现在和过去的土地利用、人类活动指数等。将这些空间数据作为水文模型的边界条件，估计人类活动对水文循环的影响。3)中国与日本联合研究项目--中国野外观测网在中国平原北部的水量平衡和水文过程。关于通量、水化学的数据是在一年多的时间里获得的。对植被和水文状态变量的卫星监测正在继续将地块尺度测量扩大到大范围。较少

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 scaleField 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 … More 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, ChinaField 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