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

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(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.