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波段散射计的地面测量系统，为利用该系统测量大面积土壤水分提供基础知识。主要研究成果如下：(1)搭建了C波段散射体安装在汽车上的测量系统，提高了地面实验的效率。利用该系统，利用搭载的E-ERS-1和J-ERS-1卫星进行了14次土壤水分的地面定标试验，其中在毗邻碧洼湖的样地进行了3次，在科孚市进行了4次。(2)研究了土壤直接采样的区域代表性。明确了土壤干燥程度越高，各采样点土壤水分的差异越大，并讨论了允许误差标准的采样间隔。(3)通过试验建立了裸地和草地土壤水分与SAR数据的经验关系式，并结合样点数据的土地分类，提出了一种制作裸地/草地土壤水分分布图的方法。

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.