近30a瀛湖流域土地利用时空变化的遥感分析

为揭示1988~2014年南水北调中线工程水源区瀛湖流域土地利用变化规律,以Landsat TM/ETM+和ALOS遥感影像为数据源,采用监督分类与目视解译相结合的分类方法,提取瀛湖流域1988~2014年5期土地利用信息,分析了土地利用时空变化特征。精度分析表明:监督分类与人工目视解译相结合方法,能够快速、准确地完成土地利用空间分布信息提取,ALOS影像总体分类精度达98%以上;但是Landsat TM/ETM+等中低分辨率遥感影像难以识别山区较分散的农村居民用地等建设用地,导致建设用地解译结果偏低。土地分类结果表明:受山谷型地貌特点影响,瀛湖流域土地利用类型呈斑块状交错分布,建设用地多呈条带状分布;目前土地利用类型以草地、耕地和林地为主,分别约占流域面积的51%,29%和18%;1988年以来建设用地的年变化率最大,高达22%,新增量来源主要是耕地,其贡献比例高达87%。

Remote sensing analysis on spatial-temporal changes of land use in Yinghu Lake Basin in past 30 years

In order to reveal the land use variation law in Yinghu Lake basin, water sources area of South-to-North Water Diversion, based on Landsat TM/ETM+ and ALOS images, combining supervised classification with manual visual interpretation method, five sets of land use information from 1988 to 2014 were extracted and the spatial and temporal variation characteristics of land utilization and its impacts on water environment were analyzed. The accuracy analysis results showed that: supervised classification combined with manual visual interpretation could extract land use spatial distribution information quickly and accurately, and the accuracy of ALOS image classification could reach more than 98%. However, the image interpretation result of construction land were lower than reality by using moderate or low resolution remote sensing images of Landsat TM/ETM+, because it was difficult to identify decentralized rural residential land in mountain area. The land use classification results show that the land use types in Yinghu Lake basin are interlaced in plaque-like texture due to the influence of geomorphic features of mountain-valley, and construction land distributes in belt form. Grass land, cultivated land and forest land are the main land use types, accounting for 51%, 29% and 18% of the basin area. The annual change rate of construction land was the biggest (more than 22%) since 1988 and the increment mainly came from cultivated land, its contribution proportion was up to 87%.