基于MODIS数据的伊犁地区草地地上生物量反演

为伊犁草地资源监测、保护及合理利用提供参考依据,利用新疆伊犁地区2012年7-8月野外草地地上生物量采样数据和同期的MODIS数据,分析了增强型植被指数(EVI)、归一化植被指数(NDVI)与实测草地地上生物量的一元线性、指数和二次多项式回归模型,并对各种回归模型进行分析比较.利用优选模型的反演结果分析了伊犁地区地上生物量的空间分布.结果表明:各植被指数都与实测生物量有较好的相关性,但以EVI指数建立的二次多项式回归模型(y = 14759x²-4758x + 1346,R²= 0.8402)较优,拟合模型平均估产精度达到 92.19%,可作为该区域草地地上生物量遥感反演模型;伊犁地区2012年平均产草量为1817 kg·hm^-2,总产草量达70.59×10⁸ kg,并且产草量随高程增加呈现先增加后减少的特征.

Aboveground Biomass Inversion of Grassland in Ili Area Using MODIS Data

The basic data involved the observed data of aboveground biomass from July to August in 2012 in Ili as well as the MODIS data during this period, and the purpose of this study was to protect and utilize grassland resources reasonably. The correlation relationships among enhanced vegetation index (EVI), normalized difference vegetation index (NDVI) and observed data of aboveground biomass were analyzed by linear regression model, quadratic polynomial regression model and index regression model. The spatial distribution of aboveground biomass in the grassland of Ili was simulated and analyzed. The results showed that a significant correlation relationship existed between vegetation index and aboveground biomass, while the quadratic polynomial regression model based on EVI(y = 14759x² - 4758x + 1346.2, R² = 0.8402) was the most suitable one, and estimation accuracy was 92.19%. The dry weight per unit area in the grassland of Ili was 1817 kg·hm^-2, and the total yield was 70.59×10⁸ kg in 2012. Along with the increasing elevation, aboveground biomass increased first and then decreased.