内蒙古锡林浩特草原GLASS LAI产品的真实性检验

结合内蒙古锡林浩特草原区域的实地测量数据和Landsat TM高分辨率遥感数据,对两景GLASS LAI产品进行真实性检验,同时以MODIS LAI产品为比照。结果表明:①GLASS LAI产品和MODIS LAI产品均高估,其中7月中旬GLASS LAI产品高估约11%,其高估的程度明显小于MODIS LAI(高估约36%),而8月末两者高估的程度相似；②GLASS LAI产品与Landsat TM反演LAI产品有较好的一致性,两期数据的决定系数R²分别达到0.72和0.58,优于MODIS LAI产品(0.61和0.27)；③GLASS LAI和MODIS LAI两个产品的误差主要来自于模型的准确性,真实性检验中数据定量化误差小于5%。结论表明:GLASS LAI产品数据在锡林浩特草原区域的观测精度和一致性都优于MODIS LAI产品数据,更适用于相关研究。

Validation of the GLASS LAI Products in Xilinhot Grassland

GLASS is a series of products newly produced by domestic team,which needs validation before further application.Validation of GLASS LAI products is implemented by field measurements in Xilinhot grassland and corresponding Landsat TM data.Besides,validation of MODIS LAI product is taken as a contrast.The results of validation indicate the over-estimation of both GLASS LAI and MODIS LAI.GLASS LAI in the mid-July over-estimates LAI is about 11%,which is obviously smaller than MODIS LAI (36% over-estimation),and the both products in the end of August show the similar extent of over-estimation.GLASS LAI products consist better with the LAI inverted by Landsat TM,and the determination coefficients R² of the two periods are respectively 0.72 and 0.58,which are both larger than MODIS LAI products (0.61 and 0.27).According to the analysis,the main source of the error of both products,GLASS LAI and MODIS LAI,is the models accuracy,and the error from the data quantification is only less than 5%.These results suggest that GLASS LAI products in Xilinhot grassland have better accuracy and consistency,and are more applicable than MODIS LAI products.