官厅水库小流域植被净初级生产力估算

Estimation on Net Primary Productivity of Vegetation in Small Watershed of Guanting Reservoir

植被是小流域的物质基础,植被净初级生产力的稳定性关系到小流域的健康和可持续发展。以官厅水库小流域为研究区,采用改进型CASA(Carnegie-Ames-Stanford Approach)模型,利用2005年、2010年和2015年以及邻近年份的每年3~11月的Landsat TM/ETM+/OLI影像数据,估算官厅水库小流域植被净初级生产力,考虑到植物的物候特征,在模型计算过程中,引入归一化差值植被指数(normalized difference vegetation index,NDVI)时间序列特征,提取地物信息,从而提高了改进型CASA模型中植被最大光能利用率使用范围的准确度。研究结果显示,2005年、2010年和2015年官厅水库小流域植被净初级生产力的总量分别为6.33×10^(8)g碳、6.73×10^(8)g碳和7.37×10^(8)g碳。

Plants are the material basis of small watersheds, and the stability of vegetation net primary productivity is related to the health and sustainable development of small watersheds. Taking the small watershed of Guanting Reservoir as the research area, adopting the improved CASA(Carnegie-Ames-Stanford Approach)model, using data of Landsat TM/ETM +/OLI images from March to November in 2005, 2010, 2015 and adjacent years to estimate the net primary productivity of vegetation in the small watershed of the Guanting Reservoir, taking into account the phenological characteristics of plants, in the calculation process of the model, the feature of time series of normalized difference vegetation index(NDVI) was introduced to extract ground information, thereby improve the accuracy of the maximum light energy utilization range in the improved CASA model. The results of the study showed that the total net primary productivity of vegetation in the small watershed of the Guanting Reservoir in 2005, 2010 and 2015 were 6.33×10^(8) g carbon, 6.73×10^(8) g carbon and 7.37×10^(8) g carbon, respectively.