青海省共和县土地沙化与土地覆盖变化遥感监测研究

以Landsat-TM、ETM＋遥感数据为信息源，对青海省共和县1987年至2002年的土地沙化和土地覆盖变化进行了监测．研究结果表明．应用TM、ETM＋等中分辨率遥感影像，对以县为单位的区域性土地沙化和土地覆盖变化进行监测是适宜的．监测精度可达90％以上；监测期内．研究区的沙化土地面积不断增加，沙化程度也迅速加深，说明沙化土地治理的效果不明显；由于草地围封面积的扩大，一、二类草地的面积显著增加，草场质量显著改善，但由于未封育草地的过牧仍很普遍，三类草地沙化仍很严重；国营农场的撤离和国家退耕还草工程的实施是农田和居民地面积减少的主要原因。

Change Monitoring of Sandy Desertification and Land Cover by Remote Sensing in Gonghe County, Qinghai

The change of sandy desertification and land cover from 1987 to 2002 were monitored based on the application of Landsat-TM and ETM satellite data.The following results were achieved:(1)The TM and ETM satellite images with mid-resolutions are available data for change monitoring of desertification and land cover at regional scale like a County,in which the monitoring accuracy may reach over 90%.(2) The sandy desertification is developing with increase of desertified area and strength of severity of desertification in study area,which shows fewer effects of activities for rehabilitation of desertified lands.(3) The areas of first and second degree rangelands were enlarged due to enclosing rangelands at large scale,so the quality of rangeland was greatly improved,but the range desertification is still common caused by overgrazing on unenclosed third degree rangeland.(4) The areas of farmland and residential area are decreased because of implementation of national project for return farmland to rangeland and withdrawal of some state-own farms.