陕甘宁青草地变化的遥感动态分析

Remote Sensing Dynamic Analysis on Grassland Changes in Shaanxi, Gansu, Ningxia and Qinghai

以陕甘宁青二十世纪八十年代中期和2000年的TM影像为信息源,运用遥感技术与地理信息系统技术结合建立了两期全区土地资源数据库,通过对从中提取的草地专题时空数据的分析得出:2000年全区有草地面积61694471hm2,占总面积的44.75%;14年间全区新增草地279028hm2,同期减少草地534071hm2,增减抵消草地净减少255043hm2,占草地面积的0.41%。全区草地减少的主要原因是草地被开垦为耕地,其次是为恢复植被而将部分草地植树变为林地以及草地沙漠化变为沙地和草地变为水域;而草地增加的主要来源是沙地变为草地,其次是林地变为草地以及耕地和水域变为草地。

With the assistance of remote sensing and geographicalinformation systems, the land resource databases in the middleof 1980's and 2000 have been established by interpreting the Landsat TM images of two times, and the extend of the databases includes all territory of Shaanxi, Gansu, Ningxia and Qinghai locating in the north China. According to the spatial-temporal information of grassland derived from the land resource databases, the following points can be concluded: in the whole region, there was 61694471hm 2 of grassland in 2000, occupying 44.75%of the territory area. Duringabout 14 years between 1986 and 2000, 279028hm 2 of new grassland had been transformed from other types of land cover, and 534071hm 2 of grassland disappearedby contraries. As the result of grassland changes, there had been255043hm 2 by 0.41% of net decrease of grassland. In the whole region, the decreased grassland was mainly reclaimedinto farmland, and secondly turned into forestry land by afforestation, sandy land by desertification and water area; the increased grassland was chiefly come from the rehabilitation of sandy land, and remnantgrassland was transformed from forestry land, farmland and water area.