基于RS和GIS的石羊河流域近50年土地覆被类型变化研究

选取石羊河流域为研究区，采用1970～2017年18期Landsat系列卫星遥感数据，通过数据处理、面向对象信息提取，获取了石羊河流域近50年土地覆被类型基础数据；运用转移矩阵、GIS分析手段，对石羊河流域不同土地类型时空变化特征进行了研究.结果表明：1）近50年来，石羊河流域自然绿洲面积总体呈逐年减少趋势，由1970年的35 717.53 km²减少到2017年的33 865.47 km²；人工绿洲面积相应增加，由5 355.79 km²增至7 208.70 km².2）耕地、天然林地、天然草地、建设用地总体呈增加趋势，耕地的增加主要由天然草地、未利用地及水域湿地转化而来，天然林地的增加主要由天然草地、未利用地转化而来，天然草地面积的增加主要由未利用地转化而来，建设用地的扩张以占用周围草地、耕地及未利用地为主.3）石羊河流域土地类型的演变，总体反映了石羊河流域生态环境趋好，绿洲区域逐渐增加.

RESEARCH ON LAND COVER CHANGES IN SHIYANG RIVER BASIN IN RECENT 50 YEARS BASED ON RS AND GIS

The Landsat series satellite remote sensing data from 1970 to 2017 are adopted for basic data to study the land covers in the Shiyang River Basin by data processing and object-oriented information extraction.The transfer matrix and GIS approaches are used to analyze the temporal and spatial variation characteristics of different land types in Shiyang River Basin.The results show that:1)In the past 50 years,the natural oasis area in Shiyang River Basin has been decreasing year by year,from 35917.53 km2 in 1970 to 33865.47 km2 in 2017;and the area of artificial oasis increased correspondingly from 5355.79 km2 to 7207.70 km2.2)The cultivated land,natural forest land,natural grassland and construction land show a generally increasing trend.The increased cultivated land is transferred mainly from natural grassland,unused land and wetland.The increase of natural forest land is mainly from natural grassland and unused land.The natural grassland area is increased mainly by the transferring of unused land.The construction land expands by taking up surrounding grassland,cultivated land and unused land.3)The evolution of land types reflects the better ecological environment and increasing oasis area of the Shiyang River Basin.