基于长时间序列影像的关中地区植被时空变化分析

Spatio-temporal Variation of Vegetation in Guanzhong Region Using Long-time Serial Images

利用1998-2010年SPOT-VGTNDVI影像对关中地区植被的时空变化进行分析。结果表明：关中地区13aNDVI（归一化植被指数）月平均值为0．508，月均NDW值在0．308-0．684变动，受6月作物收获影响，NDVI出现了5月和8月2个峰值；关中地区植被总体呈改善趋势，人类活动集中的城区、县城和部分生态脆弱区（大荔沙苑和洽川湿地）植被出现了严重的退化；降水和气温是影响NDVI变化的重要因子，同时经济建设生产活动对NDVI也有重要的影响。

In this paper, SPOT-VGT NDVI images from 1998 to 2010 were used to estimate the spatial- temporal variation of vegetation in Guanzhong region. The results showed that the monthly average of NDVI was 0. 508 and changed from 0. 308 to 0. 684 during recent 13 years. Affected by the summer har- vest in June, there were two peak values of NDVI in May and August, respectively. The total vegetation coverage within Guanzhong region presented an increasing trend obviously, while serious vegetation degra- dations were observed in urban areas and ecological sensitive areas, such as Sayuan in Dali and Qiachuan wetland. Temperature and precipitation were the important climate factors affecting the variation of vege- tation, and the value of NDVI was also under a great influence of the economic construction and producing activities.