Polarized single-scattering phase function determined for a common reflectance standard from bidirectional reflectance measurements

2018 ◽  
Author(s):  
Thomas A. Germer
Keyword(s):  
Phase Function ◽  
Single Scattering ◽  
Bidirectional Reflectance ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Reflectance Measurements

scholarly journals Modelling Laboratory Data of Bidirectional Reflectance of a Regolith Surface Containing Alumina

2011 ◽  
Vol 28 (3) ◽  
pp. 261-265 ◽  
Author(s):  
C. Bhattacharjee ◽  
D. Deb ◽  
H. S. Das ◽  
A. K. Sen ◽  
R. Gupta
Keyword(s):  
Laboratory Data ◽  
Size Composition ◽  
Single Scattering ◽  
Bidirectional Reflectance ◽  
Reflection Function ◽  
Versus Phase ◽  
Scattering Phase ◽  
Scattering Phase Function ◽  
Phase Functions ◽  
Bidirectional Reflection

AbstractBidirectional reflectance of a surface is defined as the ratio of the scattered radiation at the detector to the incident irradiance as a function of geometry. Accurate knowledge of the bidirectional reflection function for layers composed of discrete, randomly positioned scattering particles is essential for many remote sensing, engineering, and biophysical applications, as well as for different areas of astrophysics. Computations of bidirectional reflection functions for plane parallel particulate layers are usually reduced to solving the radiative transfer equation by the existing techniques. In this work we present our laboratory data on bidirectional reflectance versus phase angle for two sample sizes of alumina, 0.3 and 1 μm, for the He–Ne laser at wavelengths of 632.8 nm (red) and 543.5 nm (green). The nature of the phase curves of the asteroids depends on the parameters like particle size, composition, porosity, roughness, etc. In the present study we analyze data which are being generated using a single scattering phase function, that is, Mie theory of treating particles as a compact sphere. The well-known Hapke formula, along with different particle phase functions such as Mie and Henyey–Greenstein, will be used to model the laboratory data obtained at the asteroid laboratory of Assam University.

scholarly journals Modified analytic expression for the single-scattering phase function

2017 ◽  
Vol 66 (18) ◽  
pp. 180201
Author(s):  
Shi Ze-Lin ◽  
Cui Sheng-Cheng ◽  
Xu Qing-Shan
Keyword(s):  
Phase Function ◽  
Single Scattering ◽  
Scattering Phase ◽  
Analytic Expression ◽  
Scattering Phase Function

scholarly journals Aerosol extinction to backscatter ratio derived from passive satellite measurements

2013 ◽  
Vol 13 (1) ◽  
pp. 2351-2370
Author(s):  
F.-M. Bréon
Keyword(s):  
Phase Function ◽  
Relative Increase ◽  
Satellite Measurements ◽  
Aerosol Particle Size ◽  
Scattering Phase ◽  
Particle Size And Shape ◽  
Scattering Phase Function ◽  
Lidar Observations ◽  
Reflectance Measurements ◽  
Aerosol Type

Abstract. Spaceborne reflectance measurements from the POLDER instrument are used to study the specific directional signature close to the backscatter direction. The data analysis makes it possible to derive the extinction to backscatter ratio (EBR) which is the invert of the scattering phase function for an angle of 180° and is needed for a quantitative interpretation of lidar observations (active measurements). In addition, the multi-directional measurements are used to quantify the scattering phase function variations close to backscatter, which also provide some indication of the aerosol particle size and shape. The spatial distributions of both parameters show consistent patterns that are consistent with the aerosol type distributions. Pollution aerosols have an EBR close to 70, desert dust values are on the order of 50, while marine aerosol's is close to 25. The scattering phase function shows an increase with the scattering angle close to backscatter. The relative increase ∂lnP/∂ γ is close to 0.01 for dust and pollution type aerosols and 0.06 for marine type aerosols. These values are consistent with those retrieved from Mie simulations.

scholarly journals Spectrally Invariant Approximation within Atmospheric Radiative Transfer

2011 ◽  
Vol 68 (12) ◽  
pp. 3094-3111 ◽  
Author(s):  
A. Marshak ◽  
Y. Knyazikhin ◽  
J. C. Chiu ◽  
W. J. Wiscombe
Keyword(s):  
Radiative Transfer ◽  
Phase Function ◽  
Single Scattering ◽  
Atmospheric Conditions ◽  
Water Vapor Absorption ◽  
Mathematical Basis ◽  
Invariant Approximation ◽  
Scattering Phase ◽  
Atmospheric Radiative Transfer ◽  
Scattering Phase Function

Abstract Certain algebraic combinations of single scattering albedo and solar radiation reflected from, or transmitted through, vegetation canopies do not vary with wavelength. These “spectrally invariant relationships” are the consequence of wavelength independence of the extinction coefficient and scattering phase function in vegetation. In general, this wavelength independence does not hold in the atmosphere, but in cloud-dominated atmospheres the total extinction and total scattering phase function vary only weakly with wavelength. This paper identifies the atmospheric conditions under which the spectrally invariant approximation can accurately describe the extinction and scattering properties of cloudy atmospheres. The validity of the assumptions and the accuracy of the approximation are tested with 1D radiative transfer calculations using publicly available radiative transfer models: Discrete Ordinate Radiative Transfer (DISORT) and Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART). It is shown for cloudy atmospheres with cloud optical depth above 3, and for spectral intervals that exclude strong water vapor absorption, that the spectrally invariant relationships found in vegetation canopy radiative transfer are valid to better than 5%. The physics behind this phenomenon, its mathematical basis, and possible applications to remote sensing and climate are discussed.

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