基于核驱动模型的AMBRALS程序将用于提供MODIS的反照率和二向反射产品;该文提出一个新的几何光学核-LiTransit核,用以取代目前AMBRALS运行程序中的LiSparseR核。当植被及阴蔚总面积在视场中比例接近于;时,新核由LiSparseR核向LiDens。核自然诫。因而新核兼有公Sparse·核面LiDense核的优点,比LiSparseR核更符合几何光学模型的基本原理。对于29组地面观测数据的反演试验表明;LiTrarisit核有与LiSparse核相当的数据拟合能力,,外推到大的天顶角时有.ense核的稳定性;与LiSparseR核比较,RossThick-LiTransit的核组合更能反映直入扇出反照率随太阳天顶角变化的趋势。用NOAA AVHRR多时相数据反演的结果,也表明RossThick-LiTransit组合在反演甲更为稳定。

Kernel-driven BRDF model was applied in AMBRALS (algorithm for MODIS land surface BRDF and albedo products). In this paper, we derived a new Geometrical-Optical (GO) kernel-LiTransit-to substitute the LiSparseR kernel, which is currently used in AMBRALS. The new kernel is a natural transition from LiSparse to LiDense kernel "when vegetation become filling the field of view. LiTransit has the advantage of both LiSparse and LiDense, and accords more to the basic concept of GO model. Experimental results of 29 ground measured BRDF data sets show; LiTransit has similar data fitting ability with LiSparseR, but more stability when extrapolated to large zenith angles; comparing with Rossthick-LiSparseR, the combination of RossThick-LiTransit shows more accordance with albedo's downward tendency with respect to increasing sun zenith. Our inversion result with NOAA-AVItR data also suggests that the results derived by RossThick-LiTransit are more robust.