基于MODIS NDVI的秦岭地区植被覆盖变化研究

The vegetation dynamic in Qinling area based on MODIS NDVI

目的利用重建后的NDVI时间序列数据研究秦岭地区植被覆盖变化。方法利用非对称高斯拟合算法(AG)对秦岭地区2000—2009年MODIS NDVI时间序列数据重建,计算生长季NDVI均值、变异系数及变化趋势,分析秦岭地区2000—2009年植被的时序稳定性和变化趋势。结果①分布于秦岭山区腹地的森林和山间沟谷的灌木植被的时序稳定性较高,而分布在研究区西北部、秦岭北坡、居民聚集地周边农林混合植被,受人类活动的影响,年际波动较大;②研究区西部、东部、秦岭山区腹地,农田覆盖区域改善趋势明显。山区的森林植被和山间沟谷的灌木植被有一定程度改善趋势,但相对稳定。主要城市周边区域的植被呈明显退化趋势,以西安市的周边最为明显。结论秦岭地区植被生长状况整体呈现改善趋势,植被时序稳定性与其跟人类聚集区之间距离呈现明显的逆向分布,说明人类活动对秦岭地区植被波动影响较大。

Aim To series data. Methods investigate the vegetation dynamic changes in Qinling area with the reconstructed NDVI time Based on MODIS NDVI time series data from 2000 to 2009 in Qinling area, Asymmetric Gaussians algorithm （AG） was selected to reconstruct the time series data to reduce the negative impact of clouds, cloud shadow and atmospheric aerosols. Results ①The forest and shrub vegetation located in the hinterland of Qinling Mountains showed a higher stability in the past decade, while the cropland and mosaic cropland/non-crop vegetation located in northern slope of Qinling Mountain, as well as those areas surrounded by mountain residents, showed dramatically inter-annual fluctuation under the impact of human activities; ②The cropland located in the areas of the hinterland of Qinling Mountains showed the most obvious improvement trend. The forest and shrub veg- etation located in the hinterland of Qinling Mountain had some degree of improvement trend, which is relatively sta- ble. While the vegetation distributed in the surrounding area of major cities had a significant degradation trend, es- pecially around Xi＇an city. Conclusion The vegetation in Qinling area showed overall improvement trend during the past decade. The stability of vegetation in this area showed significant reverse distribution characteristics with its distance from the proximity of human areas, which indicated that human activities play a very important role on the vegetation dynamic in Qinling area.