[pp.57-64]

Monitoring land degradation in mountainous Mongolia by spectral unmixing of satellite imagery

Tomoo OKAYASU, UNDARMAA Jamsran and Kazuhiko TAKEUCHI （The University of Tokyo / Mongolian State University of Agriculture）

Abstract:
The privatization of livestock and the loss of the land-use management system after social system change have impacted people’s land-use patterns in Mongolia. We investigated land degradation in Delgerkhaan soum in northern mountainous Mongolia, where we found that the population moved to rivers in the summer to ensure drinking water for livestock, and to mountains in winter to protect the livestock from the strong cold wind, while steppe and low hills were neglected. Because this area is classified as a water erosion region, the most vulnerable land unit, the mountains, was analyzed by satellite remote sensing. The linear unmixing technique was applied to Landsat TM/ETM+ images from 1989 and 2000. A clear movement of surface soil material was observed, which indicates that active water erosion is progressing in the area. Water erosion causes serious and irreversible land degradation; therefore, immediate counteraction is necessary in the soum.

Key Word:
remote sensing, water erosion, desertification, Landsat, land use

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