基于长时间序列landsat数据的科尔沁沙地土地利用演变分析

以科尔沁沙地沙丘-草甸过渡带区域主要土地覆被类型为研究对象,以1987-2017年多时相Landsat TM/OLI遥感影像解译分类为基础,参考生态学植被演替研究方法,系统分析研究区30年来的土地利用/覆被动态演变规律,研究结果表明：（1）决策树法在复杂下垫面不同覆被类型的同步识别效果较好,所有影像分类精度均达到88%以上,分类效果较好,其中2017年分类精度最高为95.24%,达到了分类研究的要求;（2）研究区存在着"半灌丛-草甸地-灌丛"的植被结构特征,且整体表现为"南进北退"的变化趋势。结合土地利用动态度分析结果表明人类活动干涉下,研究区整体上遵循了半干旱区植被条件改善的一般规律,侧面反映该研究区域生态环境的持续不稳定性和脆弱性;（3）研究区覆被类型发生变化的总面积达到2623.59 hm²,总变化强度为63.76%。其中正向演替的比例为52.61%,以半灌丛面积的持续减小与沙地草甸面积的持续扩张为主要变化特征。但同时,半灌丛转为沙地的面积为184.95 hm²,表明以放牧为主的研究区同时发生着局部的逆行演变;（4）质心迁移结果反映了1987-2017年间,除人为影响较大的林地、草地以及耕地向北迁移外,其他植被类型的质心都有很明显的南迁,主要植被类型重心迁移距离依次由大到小为耕地 > 半灌丛 > 灌丛 > 沙地草甸 > 湿地草甸 > 林地。研究通过记录科尔沁沙地连续扩展的时空模式,展示了遥感-生态和时间序列影像在30 m分辨率下跟踪土地利用/覆被变化的潜力,为提高干旱半干旱区土地利用情况的动态监测效率,开展土地利用/覆被动态演变研究提供参考。

Dynamic evolution analysis of land use (land cover) in Horqin Sandy Land based on long time deries landsat data

This study takes the dune-meadow transition zone of Horqin Sandy Land as an example. Based on the interpretation and classification of 15 Landsat TM/OLI remote sensing images from 1987 to 2017, we systematically analyze the dynamic evolution law of land use/land cover in the study area in the past 30 years by referring to the ecological vegetation succession research method. The results show that: (1) With the decision tree classification algorithm, the classification accuracy of all images is more than 88%, among which the highest classification accuracy in 2017 is 95.24%, which meets the requirements of classification research. (2) There is a vegetation structure characteristic of Semi-shrub-Meadow-Shrub in the study area, and the overall change of land cover shows trend is "evolution in southern degradation in northern". Combined with the results of comprehensive dynamic change analysis of land use and land cover, it is shown that the study area follows the general law of dynamic change of land cover resources in arid and semi-arid areas under the intervention of human activities on the whole. It reflects the continuous instability and vulnerability of the ecological environment in the study area. (3) The total area of land use/land cover change in the study reached 2623.59 hm², and the overall change intensity is 63.76%. And the proportion of forward succession is 52.61%, which is mainly characterized by the continuous decrease of Semi-shrub area and the continuous expansion of Alpine meadow area. But at the same time, the area of Semi-shrub turned sandy land was 184.95 hm², indicating that local retrograde evolution occurred simultaneously in the research area dominated by grazing. (4) The centroid of main land cover have obvious southward shift, with the Forest, Meadow and Crop land shift to the north with great human influence during 1987 to 2017. And the centroid migration distance of main land cover descending is "Crop land > Semi-shrub > Shrub > Alpine meadow > Wetland meadow > Forest". By recording the continuously expanding spatial and temporal patterns in Horqin Sandy Land, the study demonstrated the potential of remote sensing-ecological and time series images to track land use changes at a resolution of 30 meters, providing a reference for improving the dynamic monitoring efficiency of land use in arid and semi-arid areas.