陕北黄土高原植被覆盖度动态变化分析研究

Study on Dynamic Change of Vegetation Coverage of Loess Plateau in Northern Shaanxi Province

以Landsat TM归一化植被指数(NDVI)为数据源,运用像元二分模型提取陕北黄土高原1990、2000、2010年夏季的植被覆盖度,分析陕北黄土高原植被覆盖度的空间变化情况。结果显示:研究区植被覆盖度呈波动上升趋势。不同等级植被覆盖度在数量和空间位置上的转移较为活跃。大于等于60%的植被覆盖度和小于等于40%的植被覆盖度在空间上呈西南—东北两个方向扩张的分布趋势。受气候和人为等因素的影响,陕北黄土高原植被改善良好。

The NDVI（ Normalized Difference Vegetation Index） of Landsat TM was taken as the data source and the dimidiate pixel model was used to extract the data of vegetation coverage with different grades of Loess Plateau in Northern Shaanxi province for the years of 1990,2000 and 2010,and the dynamic change of vegetation coverage in the study area was analyzed. The results are as follows： The vegetation coverage of this area presents a tendency of fluctuant increasing,and it transfers actively in both number and space location for different grades. the northeast for the less than 40% vegetation coverage and the southwest for the more than 60%vegetation coverage form a distribution with two directions expansion of southwest-northeast in space. The vegetation coverage of Loess Plateau in North Shaanxi province has improved well as for the affect of climate and human activities.