VII. The primary and secondary scattering of sunlight in a plane-stratified atmosphere of uniform composition

Hammad, A.; Chapman, Sydney

doi:10.1080/14786443908521165

Cited by 35 publications

(3 citation statements)

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“…However, the best accuracy may not be always desirable for a RTM. Approximative equations have been developed before computers were widely available (Hammad and Chapman, 1939;Sobolev, 1972). With regard to the growing size and frequency of remote sensing datasets, approximative and computationally fast RTMs are becoming relevant again (Kokhanovsky, 2006;Katsev et al, 2010;Carrer et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Fast and simple model for atmospheric radiative transfer

2010

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Abstract. Radiative transfer models (RTMs) are of utmost importance for quantitative remote sensing, especially for compensating atmospheric perturbation. A persistent tradeoff exists between approaches that prefer accuracy at the cost of computational complexity, versus those favouring simplicity at the cost of reduced accuracy. We propose an approach in the latter category, using analytical equations, parameterizations and a correction factor to efficiently estimate the effect of molecular multiple scattering. We discuss the approximations together with an analysis of the resulting performance and accuracy. The proposed Simple Model for Atmospheric Radiative Transfer (SMART) decreases the calculation time by a factor of more than 25 in comparison to the benchmark RTM 6S on the same infrastructure. The relative difference between SMART and 6S is about 5% for spaceborne and about 10% for airborne computations of the atmospheric reflectance function. The combination of a large solar zenith angle (SZA) with high aerosol optical depth (AOD) at low wavelengths lead to relative differences of up to 15%. SMART can be used to simulate the hemispherical conical reflectance factor (HCRF) for spaceborne and airborne sensors, as well as for the retrieval of columnar AOD.

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Section: Introductionmentioning

confidence: 99%

Fast and simple model for atmospheric radiative transfer

2010

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“…It follows from Eqgs. (3) and ( 4) that all we need to know in order to obtain the average path-lengths are the derivatives of the intensities of the emergent radiation with respect to the optical thickness of the atmosphere. These derivatives are readily found from the principles of invariance originally formulated by Ambarzumian [?°] and further elaborated by Chandrasekhar [*'].…”

Section: Rayleigh-cabannes Scatteringmentioning

confidence: 99%

Average Photon Path-Length of Radiation Emerging From Finite Atmosphere

Viik¹

1996

Proceedings of the Estonian Academy of Sciences. Physics. Mathe

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The average photon path-lengths of the emergent radiation from atmospheres in the case of isotropic and Rayleigh scattering in different orders of scattering are compared. The finite homogeneous plane-parallel atmosphere is illuminated by a parallel unpolarized beam and only the external axial field of radiation is considered. The calculations show that the impact of polarization on the average path-lengths is quite considerable, increasing towards the larger orders of scattering and decreasing towards optically thicker atmospheres. For small angles of incidence and reflection, and for small orders of scattering (n < 15), the average path-lengths of both the reflected and transmitted radiation in the case of Rayleigh scattering are always smaller than those in the case of isotropic scattering, if only the atmosphere is optically not very thick. For large angles of incidence and reflection the situation is vice versa.As a by-product of the calculations we ascertained the asymptotic behaviour of the average path-lengths which was quite similar for scalar and vector transfer. When increasing the optical thickness of an atmosphere, the average path-lengths I;" approach the value n and they do not depend on the angular variables any more. The smaller the order of scattering, the smaller the optical thickness at which this starts to happen. While for the total radiation emerging from optically thick atmospheres at 7 = 7 the average path-length is proportional to Tš, the average path-length in different orders of scattering is a linear function of 79.

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“…However, the best accuracy may not be always desirable for an RTM. Approximative equations have been developed before computers were widely available (Hammad and Chapman, 1939;Sobolev, 1972). With regard to the growing size and frequency of remote sensing datasets, approximative and computationally fast RTMs are becoming relevant again (Kokhanovsky, 2006;Katsev et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Fast and simple model for atmospheric radiative transfer

Seidel¹,

Kokhanovsky²,

Schaepman³

2010

Preprint

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Radiative transfer models (RTMs) are of utmost importance for quantitative remote sensing, especially for compensating atmospheric perturbation. A persistent trade-off exists between approaches that prefer accuracy at the cost of computational complexity, versus those favouring simplicity at the cost of reduced accuracy. We propose an approach in the latter category, using analytical equations, parameterizations and a correction factor to efficiently estimate the effect of molecular multiple scattering. We discuss the approximations together with an analysis of the resulting performance and accuracy. The proposed Simple Model for Atmospheric Radiative Transfer (SMART) decreases the calculation time by a factor of more than 25 in comparison to the benchmark RTM~6S on the same infrastructure. The approximative computation of the atmospheric reflectance factor by SMART has an uncertainty ranging from about 5% to 10% for nadir spaceborne and airborne observational conditions. The combination of a large solar zenith angle (SZA) with high aerosol optical depth (AOD) at low wavelengths lead to uncertainties of up to 15%. SMART can be used to simulate the hemispherical conical reflectance factor (HCRF) for spaceborne and airborne sensors, as well as for the retrieval of columnar AOD

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VII. The primary and secondary scattering of sunlight in a plane-stratified atmosphere of uniform composition

Cited by 35 publications

References 1 publication

Fast and simple model for atmospheric radiative transfer

Fast and simple model for atmospheric radiative transfer

Average Photon Path-Length of Radiation Emerging From Finite Atmosphere

Fast and simple model for atmospheric radiative transfer

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