中国西部地区土地利用/土地覆盖近期动态分析

在野外调查和资料收集的基础上 ,利用遥感 (RS)和地理信息系统 (GIS)技术 ,对中国西部地区 12个省 (直辖市 ) 1995年和2 0 0 0年的 6种土地利用 /覆盖类型的遥感数据进行了制图及其叠加分析。结果表明 :(1)对 1330 0个土地利用 /覆盖类型的图斑判读中 ,平均正确率 92 .92 %。同时对西部各省级土地利用 /土地覆被动态及更新成果进行的准确程度检查中 ,共获取全部 6个一级类型的动态图斑 13874 6个。地类更新平均准确率 97.71% ,勾绘图斑界线的准确率 99.85 %。 (2 )制图区域国土面积近 6 73万 km2 ,占全国土地面积的 70 %。其中 ,耕地面积 5年来增加了 12 0 .6 5万 hm2 ,比 1995年增长了 2 .4 1% ;林地面积 5年来减少了 6 1.5 0万 hm2 ,比 1995年减少了 0 .6 1% ;草地面积减少了 119.6 5万 hm2 ,比 1995年减少了 0 .5 9% ;城镇建设用地和水域面积 5年来分别增加了 19.2 5万 hm2和 17.0 4万 hm2 ,比 1995年增加了 1.36 %和 1.4 4 %。另外 ,作为西部地区主要生态环境问题之一的土地沙漠化和土地盐碱化 ,由于近年来的连续干旱以及油田开发等人为干扰的加剧 ,5 a来不可利用地面积扩大了 2 4 .2 8万 hm2 ,其中草地沙化面积占到 2 6 .94 %。

Analysis of recent land usage and survey in Western China

From 1995 to 2000, field data collections using Remote Sensing(RS) and Geographic Information System (GIS) have been conducted in 12 provinces of China' western regions. The land usage and 6 types of vegetation coverage show an average accuracy of 92.92%. Dynamic patches of the land usages and vegetation coverage types of the western provinces are analyzed. A total of 138746 of dynamic patches are obtained; and contains all major vegetation coverage types. The average reliability reaches as high as 97.71% for the classification on the dynamic land usage types and 99.85% for the demarcation of patch boundaries. The investigation shows that (1)cultivated land has increased by 1206500 hectares in recent 5years,i.e., 2.41% larger than that in 1995;(2)The forested and grass areas have decreased by 615000 and 1196500 hectares, 0.61% and 0.59% less than that in 1995, respectively;(3)The urban and wetland areas have increased by 192500 and (4)The environmental issues on desertification and salification in Western China have worsen. Unusable area has been increased by 242800 hectares in these regions due to droughts, oil explorations and other human activities, in which the desertification area occupies 26.94%.