scholarly journals Evaluation of Radar Multiple-Scattering Effects from a GPM Perspective. Part I: Model Description and Validation

2006 ◽  
Vol 45 (12) ◽  
pp. 1634-1647 ◽  
Author(s):  
A. Battaglia ◽  
M. O. Ajewole ◽  
C. Simmer
Keyword(s):  
Monte Carlo ◽  
Numerical Model ◽  
Multiple Scattering ◽  
Optical Thickness ◽  
Radiative Transfer Equation ◽  
Model Description ◽  
Pencil Beam ◽  
Scattering Effects ◽  
The Impact ◽  
Multiple Scattering Effects

Abstract A numerical model based on the Monte Carlo solution of the vector radiative transfer equation has been adopted to simulate radar signals. The model accounts for general radar configurations such as airborne/spaceborne/ground based and monostatic/bistatic and includes the polarization and the antenna pattern as particularly relevant features. Except for contributions from the backscattering enhancement, the model is particularly suitable for evaluating multiple-scattering effects. It has been validated against some analytical methods that provide solutions for the first and second order of scattering of the copolar intensity for pencil-beam/Gaussian antennas in the transmitting/receiving segment. The model has been applied to evaluate the multiple scattering when penetrating inside a uniform hydrometeor layer. In particular, the impact of the phase function, the range-dependent scattering optical thickness, and the effects of the antenna footprint are considered.

scholarly journals Effects of multiple scattering encountered for various small-angle scattering model functions

2018 ◽  
Vol 51 (5) ◽  
pp. 1455-1466 ◽  
Author(s):  
Grethe Vestergaard Jensen ◽  
John George Barker
Keyword(s):  
Multiple Scattering ◽  
Small Angle ◽  
Gaussian Function ◽  
Small Angle Scattering ◽  
Radius Of Gyration ◽  
Scattering Function ◽  
Angle Scattering ◽  
Scattering Effects ◽  
The Impact ◽  
Multiple Scattering Effects

In small-angle scattering theory and data modeling, it is generally assumed that each scattered ray – photon or neutron – is only scattered once on its path through the sample. This assumption greatly simplifies the interpretation of the data and is valid in many cases. However, it breaks down under conditions of high scattering power, increasing with sample concentration, scattering contrast, sample path length and ray wavelength. For samples with a significant scattering power, disregarding multiple scattering effects can lead to erroneous conclusions on the structure of the investigated sample. In this paper, the impact of multiple scattering effects on different types of scattering pattern are determined, and methods for assessing and addressing them are discussed, including the general implementation of multiple scattering effects in structural model fits. The modification of scattering patterns by multiple scattering is determined for the sphere scattering function and the Gaussian function, as well as for different Sabine-type functions, including the Debye–Andersen–Brumberger (DAB) model and the Lorentzian scattering function. The calculations are performed using the semi-analytical convolution method developed by Schelten & Schmatz [J. Appl. Cryst. (1980). 13, 385–390], facilitated by analytical expressions for intermediate functions, and checked with Monte Carlo simulations. The results show how a difference in the shape of the scattering function plotted versus momentum transfer q results in different multiple scattering effects at low q, where information on the particle mass and radius of gyration is contained.

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