Construction of Measurering System based on Micro-wave Scattrometer and Extraction of Soil Moisture Information.

本研究旨在构建基于C波段散射计的地基测量系统，为利用该系统进行大面积土壤水分测量提供基础知识。主要研究结果如下：（1）建立了一种车载C波段散射体测量系统，提高了地面实验的效率。利用该系统，在房总半岛的部分地块、琵琶湖附近的试验点和甲府市的试验点分别进行了14次、3次和4次搭载卫星E-ERS-1和J-ERS-1的SAR测量土壤水分的地面标定试验。(2)在土壤直接采样的区域代表性研究中，采用了土壤直接采样的方法。阐明了土壤越干燥，各采样点土壤含水量的差异越大，并讨论了允许误差准则的采样间隔。(3)通过试验得出了裸地和草地土壤水分含量与SAR数据的经验关系，并将其与SPOT数据土地分类相结合，提出了一种裸地/草地土壤水分分布图的制作方法。

The study aimed to construct a ground-based measuring system based on C-band scattrometer and to obtain fundamental knowledges on the measurement of large-areal soil moisture using the system. The major results of the study are Summarized as follows ;(1) A measuring system, in which the C-band scattromatter is mounted on a car, was constructed and it made ground-based experiments more efficient. Using the system, ground calibraton experiments for soil moisture measurement by SAR mounted Satellites, E-ERS-1 and J-ERS-1, were conducted 14 times at some plots in Boso penisula, 3 times at an experimental site near Biwa lake and 4 times in Kofu city.(2) Areal representativity of direct soil sampling was examined in earch calibration experiment. It is clarified that differences in soil moisture contents among sampling points are larger as the soil is drier, and sampling intervals for allowable error criteria are discussed.(3) Empirical relationships between SAR data and soil moisture contents in bare lands and grasslands were derived through the experiments, and a method to make a soil moisture distribution map for bare/grasslands was developed combinig the above relationships with land classification by SPOT data.