嫩江沙地沙质荒漠化程度遥感定量评价——以杜尔伯特蒙古族自治县为例

Remote Sensing quantitative evaluation for desertification degree of Nenjiang sandy land:A case study with in Durbote Autonomous County of Mongolian Minority

杜尔伯特蒙古族自治县位于嫩江沙地的中心,以杜尔伯特蒙古族自治县为例研究嫩江沙地的荒漠化程度有较好的代表性。在研究区选取63个样地实地调查荒漠化程度,同时获取研究区的ETM+遥感影像,对荒漠化主要评价因子植被盖度、生物量、裸沙占地百分比进行遥感定量反演,地表结皮和土壤质地采用定性的方法结合目视解译进行提取。在现有荒漠化评价方法的基础上,建立以像元为单位的荒漠化程度评价的定量化遥感信息模型,并输出荒漠化程度分布图。利用63个实测样地数据评价遥感信息模型的精度,被正确评价的样点数为57个,遥感信息模型对杜尔伯特蒙古族自治县荒漠化程度进行定量评价的精度达到90.5%。

Autonomous County of Mongolian Minority, Durbote is located at the center of Nenjiang sandy land, which was a good representation to study the Nenjiang sandy desertification degree. The remote sensing information model was used in this study for the quantitative evaluation of the desertification degree to this region. The desertification degree of the 63 selected plots in the study area were investigated, simultaneously the ETM ＋ remote sensing images were obtained. And from the images the main desertification appraisal factors such as vegetation cover degree, biomass and percentage of the bare sandy land occupying the land were retrieved quantitatively by remote sensing; the surface crust and the soil texture were extracted by the qualitative method combining with the visual interpretation. The quantitative remote sensing information model taking a pixel as a unit for desertification degree estimation was established and then the desertification degree map was output, which was all based on the existing desertification appraisal methods. The model precision was evaluated by using 63 measured plots, and among which 57 plots were exactly estimated. The result indicated that, the precision of the remote sensing information model for the quantitative evaluation to the desertification degree in autonomous county of Mongolian minority, Durbote was up to 90.5 %.