2001年以来甘肃民勤植被覆盖变化分析

Variation of Vegetation Coverage in Minqin County Since 2001

以甘肃民勤为研究区域,以Landsat 5 TM和Landsat 8 OLI影像为主要数据源(2001、2003、2005、2011、2013、2014年),系统分析了研究区的植被覆盖变化与驱动机制。并使用2014年遥感影像,通过像元二分模型计算了ARVI、AFRISWIR1、AFRISWIR2三种植被指数提取的覆盖度。结果显示:AFRISWIR2求算的植被覆盖度相较于ARVI、AFRISWIR1,与实际的植被覆盖度线性回归关系最好,相关指数(R2)可以达到0.84,均方根误差(RMSE)为0.7。在对2001—2014年民勤植被变化研究中得出:低植被覆盖度面积在不断减少,高中覆盖度植被面积在不断扩大,生态环境得到显著改善。通过重点植被变化区域和驱动力的分析可以得出,民勤石羊河治理工程和其他各种生态工程的实施,是民勤生态恢复最为本质的原因。

In this study,the Landsat 5 TM and Landsat 8 OLI images in 2001,2003,2005,2011,2013 and2014 were taken as the main data sources to systematically study the change of vegetation coverage and its driving factors in Minqin County,Gansu Province. ARVI,AFRISWIR1 and AFRISWIR2values were used to calculate the values of vegetation coverage with the dimidiate pixel model based on the Landsat 8 OLI images in 2014. The results showed that there was a better linear regression between the observed data of vegetation coverage and the values calculated with AFRISWIR2 than those calculated with ARVI and AFRISWIR1,R2 could be 0. 84,and the RMSE was 0. 7.The study results of vegetation coverage change in Minqin County during the period of 2001- 2014 revealed that the area with low vegetation coverage was continuously shrunk,the areas with moderate and high vegetation coverage were continually enlarged,and the ecological environment was improved significantly. The analyzed results of major vegetation change regions and driving forces revealed that the main reasons for regenerating the ecology were to implement the improvement of the Shiyang River Basin and the various ecological improving projects in Minqin County.