多源NDVI在玛纳斯河流域荒漠化监测中的应用

Application of multi-source NDVI data to desertification monitoring in the basin of the Manasi River

为了对玛纳斯河流域荒漠化进行长期准确地监测,在分析MOD13A1-NDVI（归一化植被指数）与同期8 km×8 km AVHRR-NDVI数据的基础上,建立了基于两种不同NDVI数据的荒漠化分级指标体系。利用相应的分类体系进行了流域荒漠绿洲带1982－2008年荒漠化的遥感监测,并结合19892、000和2008年8月Landsat-5/TM数据,分析了3种不同NDVI数据在空间上的差异性,并进一步分析了荒漠化演变的原因。结果表明：（1）同期AVHRR、MOD13A1和Landsat-5/TM监测结果显示出相似的空间差异性,绿洲带北部紧连古尔班通古特沙漠地区植被覆盖稀疏,NDVI较小;南部绿洲灌溉区植被覆盖较好,NDVI整体上较大。植被覆盖具有显著的空间差异性,这与地形因素、水分、热量条件、地貌形态和土壤理化性质等气候环境因子存在联系。（2）近20 a来,绿洲带外围不断向南迅速扩展,由20世纪80年代初的11 200 km^2增加到90年代末的12 672 km^2,增加了1 472 km^2;绿洲带内部以石河子垦区为中心,NDVI呈辐射状逐年线性增加。（3）近8 a来,绿洲内部变化不大,荒漠带中盐渍化土地增加显著,2008年面积为1 906 km^2,较2000年增加了1 712 km^2,东部丘间盆地被开垦耕地面积196 km^2。

We built two NDVI data classification index systems based on analysis of every ten-day 500 m×500 m MOD13A1-NDVI data and the same period＇s 8x8km AVHRR-NDVI data,for long term precise desertification monitoring in the basin of the Manasi River.Then we analyzed spatial-temporal pattern differences of three kinds of NDVI data and further give the reason of desertification,in a combination with Landsat-5/TM data of eight months in the years of 1989,2000 and 2008.The results show：（1） In the same period,the monitoring results reveal similar spatial-temporal pattern change trends interchangeably using AVHRR,MOD13A1 and Landsat-5/TM data.The north of oasis band adjacent to Gurbantonggut Desert is covered by sparse vegetation and the corresponding NDVI is small.The south oasis is covered by well-growing vegetation and the NDVI there is larger on the whole.Vegetation covering has striking spatial-temporal pattern differences associated with environmental factors,such as terrain factors, water,heat conditions,geomorphological patterns,and soil physical and chemical properties.（2） In the last twenty years,the periphery of oasis band extended rapidly to the south,from 11 200 km^2 in the mid 1980s to 12 672 km^2 in the late 1990s,with an increase of 1 472 km^2;in the interior of oasis NDVI is increasing annually in a linear trend at the reclamation area with Shihezi as the center.（3） In the last eight years,the interior of oasis had little changes,and the salinization of soil in the desertification zone has increased significantly,the area enlarged from 1 712 km^2 to 1 906 km^2 during 2000 to 2008,and the east mountain basins have been reclaimed with an area of 196 km^2.