School of Automation, Qingdao University, Qingdao, 266071, China.
Remote Sensing Information and digital Earth Center, School of Computer Science and Technology, Qingdao University, Qingdao, 266071, China.
Environ Sci Pollut Res Int. 2020 Feb;27(6):5873-5889. doi: 10.1007/s11356-019-07216-1. Epub 2019 Dec 20.
Mapping land cover changes (LCC) cover three decades over North and West Africa regions provides critical insights for the climate research that inspects the land-atmosphere interaction. LCC is a serious problem in the Earth science domain for this impacts the regional climate by modifying the distribution of terrestrial carbon stocking and roughness of the Earth's surface. In this study, the normalized difference vegetation index (NDVI) generated from advanced very high resolution radiometer (AVHRR) was used to produce a continuous set of annual land cover (LC) maps of land cover over North and West Africa between 1982 and 2015, based on the random forest classification. We used the MODIS land cover product (MCD12Q1) as a reference data for training the classifier. The result has validated using annual LC maps listed by time series and the spatio-temporal dynamics of land cover has illustrated over the last three decades. The comparison with Google Earth image 2015 shows that the overall accuracy of the simpler nine-class type of our land cover 2015 map is 76% and 2% higher than that of the MODIS map of the same year. The detection of changes indicated that over the last three decades, the urban and built-up, barren or sparsely vegetated, savannas and deciduous broadleaf forest have increased; in contrast, the open shrublands, woody savannas and water bodies have decreased.
对北非和西非地区 30 多年的土地覆盖变化(LCC)进行制图,为研究陆地与大气相互作用的气候研究提供了重要的见解。土地覆盖变化是地球科学领域的一个严重问题,因为它通过改变陆地碳储量的分布和地球表面的粗糙度来影响区域气候。在这项研究中,使用高级甚高分辨率辐射计(AVHRR)生成的归一化差异植被指数(NDVI),基于随机森林分类,生成了 1982 年至 2015 年北非和西非连续的年度土地覆盖(LC)图。我们使用 MODIS 土地覆盖产品(MCD12Q1)作为分类器的训练参考数据。使用时间序列列出的年度 LC 地图和过去 30 年的土地覆盖时空动态对结果进行了验证。与 2015 年谷歌地球图像的比较表明,我们 2015 年土地覆盖的更简单的九类地图的总体精度为 76%,比同年的 MODIS 地图高 2%。变化的检测表明,在过去的 30 年中,城市和建成区、贫瘠或稀疏植被区、热带稀树草原和落叶阔叶林面积增加;相比之下,开阔的灌木林、木质热带稀树草原和水体面积减少。