近15 a黄土高原植被覆盖时空变化及驱动力分析

Temporal and spatial variation of vegetation coverage and its driving forces in the Loess Plateau from 2001 to 2015

研究黄土高原地区植被覆盖变化及其驱动因素可以揭示研究区气候变化和人工生态调节过程对植被变化的影响。基于500 m分辨率的MODIS-NDVI数据和同期气象数据,运用均值法、斜率分析法、相关分析法及残差法,分析了2001—2015年黄土高原的植被时空演变变化特征及其驱动因素。结果表明:近15 a黄土高原植被在季度上总体都呈现增加趋势且存在一定差异,夏、秋季植被增加最为明显;黄土高原植被覆盖在空间上呈现自东南向西北递减的分布特征;植被NDVI变化在不同季节上都存在明显的空间差异;黄土高原植被NDVI对气温、降水的响应关系有明显的季节差异,并在空间上与降水的相关性显著,与温度相关性不明显;人类活动对植被覆盖变化有双重影响,其中生态恢复工程是黄土高原中部地区植被覆盖快速增加的重要因素。

It was of practical significance to understand the impact of the climate change and artificial ecological adjustment process in the Loess Plateau to the changes of vegetation coverage and its influencing factors. Based on MODIS-NDV/data with spatial resolution of500 m and the meteorological data from 2001 to 2015 ,the temporal and spatial variation of vegetation coverage and its driving forces in the Loess Plateau were studied in this paper using the averaging method, Theil-Sen slope analysis, residual analysis, correlational analysis. The results showed that the vegetation coverage had been showing an increase trend as a whole in recent 15 years,and this trend was more obvi- ous in the summer and autumn. The vegetation coverage of Loess Plateau was spatially decreased gradually from the southeast to the northwest. There was an obvious spatial variation in different seasons. In summer, the area where the vegetation coverage was showing an improving trend was the largest with an area of 342 187 km2, accounting for 54 66% of the total area while in autumn the percentage was 48.87%. There was an obvious seasonal differences with regard to the response of the vegetation coverage to the temperature and rainfall. In the spatial distribution, the cor- relation between NDVI and precipitation was significant, and the correlation between NDVI with temperature was not obvious; Human activities had dual influences on vegetation coverage, and the ecological restoration project played an important role in the rapid increase of vegetation cover in the central part of Loess Plateau.