县域尺度土地利用/覆被变化研究--以河西走廊肃州绿洲为例

采用中国科学院资源环境数据库中的全国1：10万土地资源利用分类系统，利用1988和2000年Landsat 5的4，3，2(RGB)波段合成影像解译结果，基于GIS(ARC／INFO 7．0)，用变化量、变化率、相对变化率和相对变化度等指标对肃州绿洲近12年来土地利用／覆被变化进行了研究．结果表明：2000年土地利用格局表现为以未利用地(56．19％)、耕地(27．47％)和草地(12．19％)为主，水体、农村居民点用地、林地和城镇用地仅占4．15％，各乡镇土地利用格局差异较大；12年期间，景观破碎度增加，表现在耕地、林地、草地、未利用地斑块的平均面积、周长都在减小．土地利用结构变化表现出耕地、水域明显增加，城镇用地和农村居民点也增加，草地、林地和未利用地呈减少趋势，反映出区域城镇化进程加快和生态环境恶化的趋势；采用土地利用变化量、土地利用变化率、土地利用相对变化度(率)等指标从不同角度反映了肃州绿洲LUCC的变化特点，但都表达出了LUCC较明显的区域差异；通过比较，发现土地利用相对变化度指标在揭示区域土地利用变化中优势明显．

Land use and land cover changes on the county scale-A case study of the Suzhou Oases in Hexi Corridor

A study on land use/land cover changes was carried out according to land resources classification system of 1:10 0000 from the Resources and Environmental Database of Chinese Academy of Sciences that was based on two composite Landsat 5 TM (Thematic Mapper) images of band 4, 3, 2 taken in 1988 and 2000 by GIS. The results show that: The land use pattern was dominated by unused land(56.19%), cropland(27.47%)and grassland(12.19%) in 2000. Water area, rural residences, woodland and land for urban construction only occupied 4.15% in total. The land use pattern of each town was also very different; In the 12 years between 1988 and 2000, the landscape fragmentation increased for both the mean patch area and the perimeter of cropland, woodland, grassland and unused land decreased. The changes in land use structure showed that cropland and water area had evidently increased in the same manner as the land for urban and rural use while grassland, woodland and unused land tended to decrease. It also showed a trend of speedup in urbanization and in the deterioration of the ecological environment. The application of such indices as land use change amount, land use change ratio and relative land use change rate ratio can present the characteristics of land use changes in Suzhou from different considerations. The differences among different regions are reflected in all these indices and the advantages of relative change rate in indicating land use changes are evident.