基于MODIS/EVI的内蒙古高原西部植被变化

内蒙古高原西部生态环境脆弱,是全球变化的敏感地带.为了解该区域植被覆盖的时空动态变化,根据2000—2012年MODIS/EVI影像,使用趋势分析和标准差分析方法,研究了近13年内蒙古高原西部植被生长状况及其空间格局动态变化.同时,根据《1:100万植被类型图》把研究区分为荒漠区、草原区、草甸区和灌丛区,以研究不同植被类型下的EVI变化情况.结果显示:内蒙古高原西部植被覆盖退化面积大于改善面积;植被退化区主要分布在内蒙古农牧交错带北部边缘,包含乌兰察布、呼和浩特、包头等市及大通河、疏勒河、黑河等河谷地带;植被增加区域分布在河西地区、河套地区和阿巴嘎旗附近;研究区植被稳定性存在明显的地域差异,波动较高的区域位于阴山南部、祁连山南北和阿巴嘎旗,与植被覆盖退化或者增加的区域基本吻合;仅荒漠区植被覆盖水平上升,草甸、草原区植被覆盖退化严重.

Spatio-temporal Vegetation Variation in the Western Inner Mongolia Plateau Based on MODIS/EVI

Western Inner Mongolia Plateau is a sensitive region of global change and its ecological environment is very fragile. This study is based on 2000-2012 MODIS/EVI data in order to study spatio-temporal variation of EVI in this area. We used trend analysis and standard deviation analysis to study vegetation growth of western Inner Mongolia Plateau and its spatial pattern dynamics in recent 13 years. Meanwhile, according to "1:1 000 000 vegetation map", we divided the studied area into four regions-desert, steppe, meadow and shrub area for the purpose of researching EVI variation under different vegetation types. Results are shown as follows: Degraded vegetation areas in western Inner Mongolia Plateau are larger than improved vegetation cover. Degraded vegetation areas are mainly distributed in the northern edge of the farming-pastoral transitional zone of Inner Mongolia, including cities like Ulanqab, Hohhot and Baotou as well as valleys of Datong River, Shule River and Heihe River. Improved vegetation areas consist of Hexi Corridor, Hetao Plain and the areas surrounding Abag Banner. Vegetation stability has obvious regional differences from 2000 to 2012. High-fluctuation area is located in southern foot of Yinshan Mountain, Qilian Mountain and areas surrounding Abag Banner. Vegetation areas with high fluctuation are consistent with degraded and improved region. The vegetation in Meadow area and steppe area have degraded seriously in recent years, only vegetation of desert area has a trend of improvement.