基于GEE云平台的陕北黄土高原生态修复前后植被变化及原因

Analysis of vegetation changes and causes before and after ecological restoration projectson the Loess Plateau in Northern Shaanxi based on Google Earth Engine

为探究陕北黄土高原地区生态修复前后植被覆盖时空变化特征对区域环境的响应机制,本研究利用目前最先进的地理数据分析平台Google Earth Engine(GEE),采用像元二分模型计算植被覆盖度(FVC),利用偏相关分析、多元回归残差分析和随机森林分类算法等方法,分析生态修复前后陕北黄土高原植被覆盖时空变化以及气候变化和人类活动对不同土地利用类型的响应机制。结果表明:1986—2019年,陕北黄土高原总体FVC呈现改善趋势;退耕还林前后期气温和降水与FVC的相关性不明显,但空间差异明显,植被生长对降水较为敏感;人类活动是影响陕北黄土高原FVC的主要驱动因子;在不同土地利用类型中,气候变化和人类活动对林地影响最大,对荒漠影响最小。

To investigate the response mechanism for spatial and temporal changes of vegetation cover characteristics to the regional environment before and after ecological restoration in the Loess Plateau region of Northern Shaanxi.The Google Earth Engine as the analysis platform is being used.The spatial and temporal change in vegetation covering the Loess Plateau of Northern Shaanxi before and after ecological restoration and the response mechanisms for climate change and human activities on different types of land use were analyzed by using the calculated fractional vegetation cover(FVC),partial correlation analysis,multiple regression residual analysis and random forest classification methods.The results show that the overall FVC of the Loess Plateau in Northern Shaanxi had an improving trend from 1986 to 2019,and that vegetation growth is more sensitive due to precipitation;human activities are the main drivers affecting FVC in the Loess Plateau of Northern Shaanxi;among the different types of land use,climate change and human activities have the greatest impact on woodlands and the least affected on deserts.