Angular distribution of clear sky short wavelength radiance

Harrison, A. W.; Coombes, Charles A.

doi:10.1016/0038-092x(88)90072-2

Cited by 57 publications

(19 citation statements)

References 11 publications

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“…The corresponding range in incident angles i of the sun's direct beam onto the bottom, as refracted through a level sea surface, is 0 to 48Њ. The sky radiance incident onto the sea surface simulated a clear sky using the semianalytical sky radiance model of Harrison and Coombes (1988), which is available in Hydrolight. This sky radiance model includes the effects of surface-reflected radiance as backscattered by the atmosphere.…”

Section: Brdf Effects On Bottom Reflectancementioning

confidence: 99%

Effects of optically shallow bottoms on upwelling radiances: Bidirectional reflectance distribution function effects

Mobley

Zhang

Voss

2003

Limnology & Oceanography

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Radiative transfer simulations were carried out for a variety of measured and modeled benthic bidirectional reflectance distribution functions (BRDFs), incident lighting conditions, bottom depths, and water inherent optical properties. These simulations quantify the errors that occur in predictions of above-surface remote-sensing reflectances and in-water upwelling radiances if non-Lambertian ocean bottoms are replaced by Lambertian bottoms having the same irradiance reflectance. We found that when computing water-leaving radiances, non-Lambertian BRDFs can be replaced by a Lambertian BRDF having the same irradiance reflectance, with errors seldom greater than 10% and often much less, for considerations of above-surface ocean-color remote sensing by Ocean Portable Hyperspectral Imager for Low-Light Spectroscopy (Ocean PHILLS) or similar systems using near-nadir viewing directions. The crucial measurement to make in characterizing the reflectance properties of a benthic surface for such applications is the spectral irradiance reflectance.

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Section: Brdf Effects On Bottom Reflectancementioning

confidence: 99%

Effects of optically shallow bottoms on upwelling radiances: Bidirectional reflectance distribution function effects

Mobley

Zhang

Voss

2003

Limnology & Oceanography

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“…The angular solar radiance distribution N (θ ′ , ψ ′ ) was calculated using the model of Harrison and Coombes (1988). N (θ, ψ) was normalized such that a sum over the hemisphere yielded a value of 1.0.…”

Section: Launching Of Raysmentioning

confidence: 99%

A scalable plant-resolving radiative transfer model based on optimized GPU ray tracing

Bailey

Overby

Willemsen

et al. 2014

Agricultural and Forest Meteorology

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A new model for radiative transfer in participating media and its application to complex plant canopies is presented. The goal was to be able to efficiently solve complex canopy-scale radiative transfer problems while also representing sub-plant heterogeneity. In the model, individual leaf surfaces are not resolved, but rather vegetation is aggregated into isothermal volumes. Using the leaf angle distribution and leaf area density functions, the volumes realistically augment the radiation field through absorption and anisotropic scattering and reemission. The volumes are grouped to form individual plants, and individual plants are grouped to form entire canopies. The model increases efficiency by performing ray tracing calculations on graphics processing units (GPUs) using the NVIDIA R ⃝ OptiX TM and CUDA TM frameworks, and through efficient algorithms for radiation reflection, scattering, and emission. This efficiency allows for realistic representation of heterogeneity, while also allowing for the solution of problems with very large domains (∼ 10 5 trees) quickly on an inexpensive desktop workstation. Problem execution time scaled nearly linearly with the number of discrete elements in the domain. Model results are compared with experimental data collected from an array of radiation sensors within and above a grapevine canopy and an isolated tree. Agreement between simulated and measured values of shortwave and longwave radiation were very good, with model predictions generally within the expected measurement accuracy.

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“…However, the intensity is not only related to wavelength, but also the scattering angle. To properly compute the distribution of skylight intensity in different directions, this paper adopts a clear skylight radiance distribution model built by Harrison and Coombes [42], the expression is shown in Equation (8).…”

Section: Intensity and Polarization Of Skylightmentioning

confidence: 99%

Polarization Patterns of Transmitted Celestial Light under Wavy Water Surfaces

Zhou

Wang

et al. 2017

Remote Sensing

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This paper presents a model to describe the polarization patterns of celestial light, which includes sunlight and skylight, when refracted by wavy water surfaces. The polarization patterns and intensity distribution of refracted light through the wave water surface were calculated. The model was validated by underwater experimental measurements. The experimental and theoretical values agree well qualitatively. This work provides a quantitative description of the repolarization and transmittance of celestial light transmitted through wave water surfaces. The effects of wind speed and incident sources on the underwater refraction polarization patterns are discussed. Scattering skylight dominates the polarization patterns while direct solar light is the dominant source of the intensity of the underwater light field. Wind speed has an influence on disturbing the patterns under water.

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Angular distribution of clear sky short wavelength radiance

Cited by 57 publications

References 11 publications

Effects of optically shallow bottoms on upwelling radiances: Bidirectional reflectance distribution function effects

Effects of optically shallow bottoms on upwelling radiances: Bidirectional reflectance distribution function effects

A scalable plant-resolving radiative transfer model based on optimized GPU ray tracing

Polarization Patterns of Transmitted Celestial Light under Wavy Water Surfaces

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