基于MODIS NDVI的青海高原植被覆盖时空变化特征分析

Spatiotemporal variation of the vegetation coverage in Qinghai Plateau based on MODIS NDVI data

以2000-2014年MODIS NDVI数据为基础,综合利用MVC、SG滤波、Mann-Kendall检验等方法,对青海高原植被覆盖时空变化特征及其驱动因子进行了分析和研究。结果表明,受水资源、地形地貌类型等因素影响,研究区植被覆盖程度从东南向西北方向递减,植被生长发育周期区域差异性大,2000m以下的河湟谷地生长期最长,温度、降水量是其季节变化的重要驱动因子。15年间植被覆盖显著下降区域占11.3%,主要分布在柴达木盆地中部和青海高原东北部地区,32.1%的区域植被覆盖显著上升,分布在研究区中东部、青海湖、青南高原中部等地区,降雨量的增加和人类的改造活动是青海高原植被覆盖改善的重要影响因素。

The spatiotemporal variation of vegetation coverage and its driving factor in Qinghai plateau from 2000 to 2014 were analyzed and studied based on MVC,SG filter,Mann- Kendall test methods and MODIS NDVI data. The results showed that the vegetation coverage distribution was diminished from southeast to northwest result from water resource and topography. The vegetation growing period had a big differentiation with the different altitude,and the altitude less than 2000 meters called Hehuang Valley had the longest period. The temperature and precipitation were the important driving factors for seasonal variation of vegetation cover. The prominent decreasing regions accounting for 11. 3% of the area mainly distributed on the middle Qaidam basin and northeast,and the prominent increasing accounting for 32. 1% mainly distributed on mid- east,Qinghai Lake and mid- south of the plateau. The research also indicated that the increasing of precipitation and human activities were significantly improved the vegetation coverage of Qinghai plateau.