2000-2014年蒙古高原植被覆盖时空变化特征及其对地表水热因子的响应

The spatial and temporal variation of vegetation cover in Mongolian Plateau and its response to surface hydrothermal factors from 2000 through 2014

利用MODIS NDVI数据、同期地表水热组合数据和植被类型数据,对2000-2014年蒙古高原生长季和三季(春、夏、秋季)植被覆盖时空演变特征及其对地表水热因子响应模式进行分析。研究表明:这15 a来,蒙古高原生长季及三季归一化植被指数NDVI均呈增加趋势,且呈显著增加趋势区域主要集中在内蒙古地区,一定程度上反映了该地区生态恢复工程的有效性。研究区植被覆盖变化与地表水分指数LSWI有密切的关系,因此证明研究区植被覆盖的增加归因于自然和人为因素的共同作用。不同类型植被NDVI均呈增加趋势,其中荒漠植被NDVI增加最明显,森林植被增加平缓,且存在季节性差异。此外,不同类型植被NDVI受水热因子影响也存在季节性差异。

In this paper,annual and seasonal variations of vegetation coverage and its response to land surface hydrothermal conditions in Mongolian Plateau during 2000-2014 were analyzed by using MODIS NDVI dataset and corresponding hydrothermal data,including land surface water index and land surface temperature. The results indicated that the annual and seasonal vegetation coverages had increased during 2000-2014 in Mongolian Plateau,especially in the Inner Mongolia Region,showing the effectiveness of the ecological restoration project.The vegetation coverage in the study area has close relationship with LSWI（ land surface water index）. It is demonstrated that the vegetation coverage is increasing due to a combination action of natural and human factors.The normalized difference vegetation index（ NDVI） of various vegetation types is increasing too,especially in desert,but NDVI of forest increasing gently. In addition,there are seasonal differences in the influence of hydrothermal factors on NDVI of different types of vegetation.