CAJ | 학술논문

利用4种地表类型共16个地面站点的MISR 9个角度反射率数据产品和MODIS反射率数据产品(MOD09A1),对比两种传感器获取的地表方向反射观测数据和用BRDF模型参数产品计算的方向反射数据,分析了这两种BRDF模型参数的外摊能力.研究结果表明:(1)MISR和MODIS BRDF模型参数数据产品都具有一定的对观测数据以外方向反射的外推能力,相比用MISR BRDF模型参数数据外推到相应MODIS观测角度方向反射的结果一致性较强.(2)采用两种BRDF模型参数推算的方向反射率与观测数据的接近程度有随观测天顶角的增大而减弱的趋势,在观测天顶角较小时一致性较好.(3)所用数据处理结果显示,MODISBRDF模型参数数据产品在近垂直主平面方向反射率推算结果相比近主平面方向的推算结果更接近观测数据.
이용4충지표류형공16개지면참점적MISR 9개각도반사솔수거산품화MODIS반사솔수거산품(MOD09A1),대비량충전감기획취적지표방향반사관측수거화용BRDF모형삼수산품계산적방향반사수거,분석료저량충BRDF모형삼수적외탄능력.연구결과표명:(1)MISR화MODIS BRDF모형삼수수거산품도구유일정적대관측수거이외방향반사적외추능력,상비용MISR BRDF모형삼수수거외추도상응MODIS관측각도방향반사적결과일치성교강.(2)채용량충BRDF모형삼수추산적방향반사솔여관측수거적접근정도유수관측천정각적증대이감약적추세,재관측천정각교소시일치성교호.(3)소용수거처리결과현시,MODISBRDF모형삼수수거산품재근수직주평면방향반사솔추산결과상비근주평면방향적추산결과경접근관측수거.
The Bidirectional Reflectance Distribution Function (BRDF) of land surfaces specifies the behavior of surface directional reflectance as a function of illumination and viewing angles. The bidirectional reflectance products of the Moderate resolution Imaging Spectroradiometer (MODIS) and the Multiangle Imaging Spectroradiometer (MISR) and their BRDF model parameters products have been available respectively. Since the BRDF model parameters are inverted from limited angular observations for a given pixel, it is necessary to evaluate whether they can effectively characterize the directional reflectance in other viewing directions. In this study, we choose four kinds of land cover types to analyze the representation of MISR and MODIS BRDF model parameters, by comparing the directional reflectance extrapolated using the BRDF model parameters with the observed directional reflectance. The results show that: (1) both MODIS and MISR BRDF model parameters have better representation on directional reflectance at some viewing directions. Especially MISR BRDF model parameters have preferable representations at MODIS viewing directions; (2) the representative ability of both BRDF model parameters tends to weaken when the viewing zenith angle increases; (3) from the analysis of the observed data set shown in this paper, it seems that the representative ability of MODIS BRDF models is better near cross-principal plane than that near principal plane.