scholarly journals Effect of Scattering Angle on Earth Reflectance

2021 ◽  
Vol 2 ◽  
Author(s):  
Alexander Marshak ◽  
Alfonso Delgado-Bonal ◽  
Yuri Knyazikhin
Keyword(s):  
Upper Bound ◽  
Amazon Basin ◽  
Strong Increase ◽  
Bidirectional Reflectance ◽  
Ice Clouds ◽  
Scattering Angle ◽  
Near Ir ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Vegetation Models

After March 2020 the range of scattering angle for DSCOVR EPIC and NISTAR has been substantially increased with its upper bound reaching 178°. This provides a unique opportunity to observe bi-directional effects of reflectance near backscattering directions. The dependence of the top-of-atmosphere (TOA) reflectance on scattering angle is shown separately for ocean and land areas, for cloudy and clear pixels, while cloudy pixels are also separated into liquid and ice clouds. A strong increase of TOA reflectance towards backscattering direction is reported for all components (except cloudless areas over ocean). The observed increase of reflectance is confirmed by cloud and vegetation models. The strongest correlation between TOA reflectance and scattering angle was found near IR where contribution from vegetation dominates. Surface Bidirectional Reflectance Factor (BRF) acquired by DSCOVR EPIC and Terra MISR sensors over the Amazon basin is used to demonstrate the bi-directional effects of solar zenith and scattering angles on variation of reflected radiation from rainforest.

Simulation and Sensibility Analysis of Earth Surface Bidirectional Reflectance Factor Based on Radiosity

2018 ◽  
Vol 55 (9) ◽  
pp. 092802
Author(s):  
甄治钧 Zhen Zhijun ◽  
陈圣波 Chen Shengbo ◽  
覃文汉 Qin Wenhan ◽  
李健 Li Jian ◽  
孟凡晓 Meng Fanxiao ◽  
...  
Keyword(s):  
Earth Surface ◽  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Sensibility Analysis

Development of a Spectral Error Model for Surface Bidirectional Reflectance Factor (BRF) Retrieval

1998 ◽  
Vol 24 (2) ◽  
pp. 128-132 ◽  
Author(s):  
M. Bergeron ◽  
N.T. O'Neill ◽  
A. Royer ◽  
P.M. Teillet
Keyword(s):  
Error Model ◽  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor

Effect of soil surface roughness and scene components on soil surface bidirectional reflectance factor

2012 ◽  
Vol 92 (2) ◽  
pp. 297-313 ◽  
Author(s):  
Z. Wang ◽  
C. A. Coburn ◽  
X. Ren ◽  
P. M. Teillet
Keyword(s):  
Surface Roughness ◽  
Rough Surface ◽  
Zenith Angle ◽  
Smooth Surface ◽  
Soil Surface ◽  
Bidirectional Reflectance ◽  
Imaging Spectrometer ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Soil Surface Roughness

Wang, Z., Coburn, C. A., Ren, X. and Teillet, P. M. 2012. Effect of soil surface roughness and scene components on soil surface BRF. Can. J. Soil Sci. 92: 297–313. Bidirectional Reflectance factor (BRF) data of both rough [surface roughness index (SRI) of 51%] and smooth soil surfaces (SRI of 5%) were acquired in the laboratory under 30° illumination zenith angle using a Specim V10E imaging spectrometer and an Ocean Optics non-imaging spectrometer mounted on the University of Lethbridge Goniometer System version 2.5 (ULGS-2.5) and version 2.0 (ULGS-2.0), respectively. Under controlled laboratory conditions, the rough soil surface exhibited higher spectral reflectance than the smooth surface for most viewing angles. The BRF of the rough surface varied more than the smooth surface as a function of the viewing zenith angle. The shadowing effect was stronger for the rough surface than for the smooth surface and was stronger in the forward-scattering direction than in the backscattering direction. The pattern of the BRF generated with the non-image based data was similar to that generated with the whole region of interest (ROI) of the image-based data, and that of the whole ROI of the image-based data was similar to that of the illuminated scene component. The BRF of the smooth soil surface was dominated by illuminated scene component, i.e., the sunlit pixels, whereas the shaded scene component, i.e., the shaded pixels, was a larger proportion of the BRF of the rough soil surface. The image-based approach allowed the characterization of the contribution of spatial components in the field of view to soil BRF and improved our understanding of soil reflectance.

scholarly journals Instantaneous Top-of-Atmosphere Albedo Comparison between CERES and MISR over the Arctic

2018 ◽  
Vol 10 (12) ◽  
pp. 1882 ◽  
Author(s):  
Yizhe Zhan ◽  
Larry Di Girolamo ◽  
Roger Davies ◽  
Catherine Moroney
Keyword(s):  
Solar Zenith Angle ◽  
Radiant Energy ◽  
Energy System ◽  
Radiation Budget ◽  
The Arctic ◽  
Bidirectional Reflectance ◽  
Retrieval Accuracy ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Relative Root

The top-of-atmosphere (TOA) albedo is one of the key parameters in determining the Arctic radiation budget, with continued validation of its retrieval accuracy still required. Based on three years (2007, 2015, 2016) of summertime (May–September) observations from the Clouds and the Earth’s Radiant Energy System (CERES) and the Multi-angle Imaging SpectroRadiometer (MISR), collocated instantaneous albedos for overcast ocean and snow/ice scenes were compared within the Arctic. For samples where both instruments classified the scene as overcast, the relative root-mean-square (RMS) difference between the sample albedos grew as the solar zenith angle (SZA) increased. The RMS differences that were purely due to differential Bidirectional Reflectance Factor (BRF) anisotropic corrections ( σ A D M ) were estimated to be less than 4% for overcast ocean and overcast snow/ice when the SZA ≤ 70°. The significant agreement between the CERES and MISR strongly increased our confidence in using the instruments overcast cloud albedos in Arctic studies. Nevertheless, there was less agreement in the cloud albedos for larger solar zenith angles, where the RMS differences of σ A D M reached 13.5% for overcast ocean scenes when the SZA > 80°. Additionally, inconsistencies between the CERES and MISR scene identifications were examined, resulting in an overall recommendation for improvements to the MISR snow/ice mask and a rework of the MISR Albedo Cloud Designation (ACD) field by incorporating known strengths of the standard MISR cloud masks.

Polarised bidirectional reflectance factor measurements from soil, stones, and snow

2009 ◽  
Vol 110 (17) ◽  
pp. 1940-1953 ◽  
Author(s):  
Jouni Peltoniemi ◽  
Teemu Hakala ◽  
Juha Suomalainen ◽  
Eetu Puttonen
Keyword(s):  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor

Polarised bidirectional reflectance factor measurements from vegetated land surfaces

2009 ◽  
Vol 110 (12) ◽  
pp. 1044-1056 ◽  
Author(s):  
Juha Suomalainen ◽  
Teemu Hakala ◽  
Eetu Puttonen ◽  
Jouni Peltoniemi
Keyword(s):  
Bidirectional Reflectance ◽  
Bidirectional Reflectance Factor ◽  
Reflectance Factor ◽  
Land Surfaces
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