Extraction of snowpack parameters from the microwave remote sensing data obtained by the earth observation satellites.

(1)从SAR获得的数据中提取积雪参数。利用积雪的散射模型，分析了JERS-1和ERS-1上安装的合成孔径雷达(SAR)测量的后向散射系数。分析结果表明，JERS-1/SAR对于测量湿积雪深度和水分是有效的，ERS-1/SAR对于测量干积雪深度和粒度是有效的。通过ERS-1/SAR数据与地面实况数据的对比，验证了该分析方法在高空间分辨率积雪参数估计中的有效性。(2)从MSR数据中提取积雪参数利用MOS-1和MOS-1b上安装的微波扫描辐射计(MSR)的积雪发射模型进行分析，得到待测量的亮温和发射率。亮温取决于不同粒度、不同观测频率的积雪层结。现阶段，利用MSR卫星搭载的积雪遥感对北海道这样大范围的季节和年积雪进行宏观估计是可行的，但需要对地形、森林等影响进行精确分析，并提高空间分辨率。(3)便携式FM-CW雷达的研制开发了便携式FM-CW雷达系统，用于采集积雪的深度、密度、地层等地面真实数据。利用系统在积雪表面运动采集的数据，合成积雪内部层状结构的地形并在LCD上显示，实验结果表明该便携式雷达在卫星微波观测中采集积雪地面实况数据是有效的。

(1) Extraction of snowpack paramters from the data obtained by the SAR.Using a scattering model for the snowpack, analyzes were carried out for obtaining the backscattering coefficient to be measured by the Synthetic Aperture Radar(SAR) mounted on JERS-1 and ERS-1.Results of the analyzes show that JERS-1/SAR is effective for the measurement of depth and water content within the wet snowpack, and ERS-1/SAR is effective for the measurement of depth and grain size within the dry snowpack. And also, results of comparison between the data obtained by ERS-1/SAR and ground truth data show a validity of this method of analysis for the estimation of snowpack parameters with high spatial resolution.(2) Extraction of snowpack parameters from the data obtained by the MSR.Using a emission model for the snowpack, analyzes were carried out for obtaining the brightness temperature and emissivity to be measured by the Microwave Scanning Radiometer (MSR) mounted on MOS-1 and MOS-1b. The brightness temperature depended on the stratification of the snowpack having various grain sizes and also observed frequencies.At the present stage, the remote sensing of the snowpack by MSR mounting on satellite has an availability for the macroscopic estimation of seasonal and annual snowcover such a vast extent as Hokkaido, though the precise analyzes on the effects such as terrain, forest and so forth should be needed together with improvement in the spatial resolution.(3) Development of a portable FM-CW radar.A portable FM-CW radar sysytem for collecting the ground truth data of snowpack, such as depth, density, stratigraphy and so on, was developed. The topography of the internal layred structure in the snowpack was composed and displayd on the LCD, using the data collected by the system moving on the snow surface.Experimental results showed the validity of this portable radar for collecting the ground truth data of snowpack in the microwave observation from satellites.