基于MOD09产品的水稻叶面积指数和叶绿素含量的遥感估算模型

基于中分辨率成像光谱仪MODIS (moderate resolution imaging spectroradiometer)反射率产品MOD09的同步野外实测水稻叶面积指数（LAI）和叶绿素含量（Chltot）相关数据，探寻用MOD09产品提取的植被指数(VIs)与水稻LAI和Chltot之间的相关性以及估算模型. 结果表明，MOD09计算的VI数值比MODIS前3个波段数值偏大，归一化植被指数NDVI (normalized difference vegetation index) 值普遍比增强性植被指数EVI(enhanced vegetation index) 值大. 通过4种不同植被指数与LAI相关性的比较，得出EVI与LAI的相关关系在水稻各个生育期优于其它植被指数，基于MOD09-EVI建立水稻LAI的遥感估算模型，经实际地面同步数据检验, 模型精度较高. 因而, MOD09-EVI较适用于水稻叶面积指数的实时遥感监测. MOD09红波段与Chltot之间的相关性在水稻前中期达到显著，并且优于其它植被指数，基于MOD09红波段建立了水稻前中期Chltot的估算模型并进行了精度检验. 除水稻孕穗期叶绿素含量估算模型的相关系数和F值通过了显著性检验外, 其余生育期估算模型都没有通过显著性检验.

Estimation models of rice LAI and Chlorophyll content based on MOD09

The MODIS (moderate-resolution imaging spectroradiometer) surface reflectance product MOD09, which was strictly corrected by NASA, can be widely applied to monitor the change of land vegetation. In this paper, a quasi and synchronous experiment of MODIS sensor was performed, and the rice leaf area index (LAI) and chlorophyll content (Chltot) were measured. The relationships between the vegetation indices (VIs) derived from MOD09 and the rice LAI and Chltot were analyzed, and the estimation models were established. The VIs values derived from MOD09 were higher than those in the first three bands of MOD09, and EVI value was lower than NDVI value. In comparing with other Vis, EVI had a better relationship with LAI at different rice growth stages. MOD09-EVI was selected to construct the estimation model of rice LAI, and validated by other in situ sampling plot data to be more precise, suggesting MOD09-EVI was the best index to monitor rice LAI. There was a significant correlation between MOD09-Red band and Chltot at early and medium rice growth stages. The estimation model of rice canopy Chltot based on MOD09-Red band was established and validated, and no models were significantly efficient, except the estimation model of Chltot at booting stage.