| Title | An Evaluation of Kernel-Driven Bidirectional Models Using PARABOLA Measurements |
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| Author | Li, Z; Moreau, L; Cihlar, J; Deering, D |
| Source | Canadian Journal of Remote Sensing 23, 2, 1997 p. 120-130, https://doi.org/10.1080/07038992.1997.10855194 |
| Year | 1997 |
| Alt Series | Earth Sciences Sector, Contribution Series 20042138 |
| Publisher | Informa UK Limited |
| Document | serial |
| Lang. | English |
| Media | paper; on-line; digital |
| File format | pdf |
| Released | 2014 07 31 |
| Abstract | The kernel-driven biderectional models (KDBM) are employed increasingly to account for the bidirectional dependence of reflectance. This study presents an evaluation of various KDBMs using surface
bidiectional measurements acquired by PARABOLA. Numerous tests were conducted by fitting the KDBMs to reflectance data available in a limited and non-limited viewing domain for fixed and variable solar zenith (SZ) angles at the surface and top of the
atmosphere (TOA). The performance was evaluated by comparing the fitness of observed bidirectional dependence and albedos from observations and KDBMs. It varies considerably among the KDBMs when samples are confined to such a limited domain as the
principle plane wherein the NOAA/AVHRR data used in this study cover the northern regions. When the angular samples are distributed throughout the entire viewing domain, the majority of KDBMs lead to good estimates of albedo with relative
uncertainties less than 10%, but their fits to the bidirectional dependence may differ drastically. Moderate errors ensued when a KDBM tuned to a specific SZ is applied to other SZ angles. Most KDBMs perform even better when applied to TOA
measurements. The best performance, for the sites we investigated, is achieved by the combination of Roujean et al.'s surface scattering kernel and ross' volume scattering kernel with a relative uncertainty in albedo estimate merely 2%. |
| GEOSCAN ID | 218940 |
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