A method for improving hotspot directional signatures in BRDF models used for MODIS

Autor: Alan H. Strahler, Miguel O. Román, Jing M. Chen, Crystal B. Schaaf, François-Marie Bréon, Hu Zhang, E. Saenz, Ziti Jiao, Yadong Dong, Zhuosen Wang, Xiaowen Li, Michael J. Hill, Charles K. Gatebe, R. Poudyal
Přispěvatelé: Beihang University (BUAA), Department of Environmental, Earth and Ocean Sciences [Boston] (EEOS), University of Massachusetts [Boston] (UMass Boston), University of Massachusetts System (UMASS)-University of Massachusetts System (UMASS), China National Research Center of Intelligent Equipment for Agriculture [Beijing] (NRCIEA), Chinese Academy of Agricultural Sciences (CAAS), NASA Goddard Space Flight Center (GSFC), University of North Dakota [Grand Forks] (UND), University of Toronto, Beijing Normal University (BNU), Modélisation INVerse pour les mesures atmosphériques et SATellitaires (SATINV), Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Boston University [Boston] (BU), Beihang University, AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Centre National de la Recherche Scientifique (CNRS), Centre de Sciences Nucléaires et de Sciences de la Matière (CSNSM), Université Paris-Sud - Paris 11 (UP11)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Rok vydání: 2016
Předmět:
linear RTLSR model
010504 meteorology & atmospheric sciences
Remote sensing application
0211 other engineering and technologies
Soil Science
02 engineering and technology
01 natural sciences
Narrowband
Hotspot (geology)
hotspot kernel
hotspot signature
Computers in Earth Sciences
[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces
environment
Anisotropy
airborne measurements
ComputingMilieux_MISCELLANEOUS
021101 geological & geomatics engineering
0105 earth and related environmental sciences
Remote sensing
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean
Atmosphere
[SDE.IE]Environmental Sciences/Environmental Engineering
Geology
BRDF
CAR
multiangle remote sensing
Exponential function
MODIS
13. Climate action
A priori and a posteriori
POLDER
Bidirectional reflectance distribution function
Free parameter
Zdroj: Remote Sensing of Environment
Remote Sensing of Environment, Elsevier, 2016, 186, pp.135-151. ⟨10.1016/j.rse.2016.08.007⟩
Remote Sensing of Environment, 2016, 186, pp.135-151. ⟨10.1016/j.rse.2016.08.007⟩
ISSN: 0034-4257
1879-0704
Popis: International audience; The semi-empirical, kernel-driven, linear RossThick-LiSparseReciprocal (RTLSR) Bidirectional Reflectance Distribution Function (BRDF) model is used to generate the routine MODIS BRDF/Albedo product due to its global applicability and the underlying physics. A challenge of this model in regard to surface reflectance anisotropy effects comes from its underestimation of the directional reflectance signatures near the Sun illumination direction; also known as the hotspot effect. In this study, a method has been developed for improving the ability of the RTLSR model to simulate the magnitude and width of the hotspot effect. The method corrects the volumetric scattering component of the RTLSR model using an exponential approximation of a physical hotspot kernel, which recreates the hotspot magnitude and width using two free parameters (C1 and C2, respectively). The approach allows one to reconstruct, with reasonable accuracy, the hotspot effect by adjusting or using the prior values of these two hotspot variables. Our results demonstrate that: (1) significant improvements in capturing hotspot effect can be made to this method by using the inverted hotspot parameters; (2) the reciprocal nature allow this method to be more adaptive for simulating the hotspot height and width with high accuracy, especially in cases where hotspot signatures are available; and (3) while the new approach is consistent with the heritage RTLSR model inversion used to estimate intrinsic narrowband and broadband albedos, it presents some differences for vegetation clumping index (CI) retrievals. With the hotspot-related model parameters determined a priori, this method offers improved performance for various ecological remote sensing applications; including the estimation of canopy structure parameters.
Databáze: OpenAIRE
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