基于MODIS的南方草地NPP遥感估算与应用

草地NPP遥感模型的构建是实现大面积草地NPP估算的有效途径之一。以MODIS-NDVI数据为基础,以南方草山草坡为研究对象,结合野外实测数据,分析了草地NPP与NDVI之间的关系,同时构建了以NDVI为自变量以及水热条件为调节因子的南方草地NPP遥感估算模型,并通过不同年份独立的实测数据对模型进行了验证。结果表明,南方草地NPP与NDVI之间存在5种相关类型,均达到了极显著水平。NPP的模拟值和实测值之间具有很好的相关性和一致性,5种草地类型R²分别为0.902 2,0.826 6,0.871 2,0.887 7和0.875 5,均达到了极显著水平,均方根误差(RMSE)和相对均方根差(RRMSE)均较小。表明模型的模拟结果比较可靠,为南方草地NPP估算及草地资源管理提供了一种有效的方法。

Remote sensing estimation and application of grassland NPP based on MODIS data in southern China

The construction of estimation model with remote sensing for grassland net primary productivity (NPP) is one of the effective ways to realize grassland NPP estimation in large areas. This paper analyzed the relationships between NPP and normalized difference vegetation index (NDVI) based on the moderate-resolution imaging spectroradiometer (MODIS) data and field measurement data. The estimation model of NPP in the southern grassy mountains and slopes was constructed with NDVI as the independent variable and hydrothermal conditions as regulatory factors, and the model was validated by independent observed data in different years. There were five relevant types between the grassland NPP and NDVI, and the correlations all reached a very significant level. There were good correlation and consistency between the simulated and observed NPP, and R² were 0.902 2, 0.826 6, 0.871 2, 0.887 7, 0.875 5, respectively, all achieved a very significant level too. The RMSE and RRMSE between observed and simulated NPP were smaller. It indicated that the model was reliable, and the results of above provided an effective method for the estimation of grassland NPP and the resource management in southern china.