Presented here are expressions for the P(N) approximation for light propagation in scattering media in the frequency domain. To elucidate parametric dependencies, the derivation uses normalization of the resulting expressions to either the total interaction coefficient or the reduced total interaction coefficient. For the latter case, a set of reduced phase function coefficients are introduced. Expression of the P(N) approximation as a conventional eigenvalue problem facilitates computation of the eigenvalues or attenuation coefficients. This approach is used to determine the attenuation coefficients in the asymptotic regime over the full values of the scattering albedo and reduced scattering albedo (0 to 1) and all positive values of the asymmetry factor (0 to 1). Frequency-domain measurements yield a sensitivity to turbid media optical properties for reduced scattering albedos as small as 0.2. P(N) calculations are used to assess the magnitude of errors associated with the P1 and P3 approximations over a range of scattering albedo, phase function, and modulation frequency.
Download full-text PDF |
Source |
|---|---|
| http://dx.doi.org/10.1364/ao.44.002058 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Impact of aerosol-photolysis interaction on the ozone concentration in the upper boundary layer on Mountain Everest.
Sci Total Environ
January 2025
SKL-ESPC & SEPKL-AERM, College of Environmental Sciences and Engineering and Center for Environment and Science, Peking University, Beijing 100871, China.
Previous research has revealed that, during the late afternoon, the ozone (O3) concentration tends to elevate at the northern perimeter of Mount Everest (5200 m above sea level). This increase is attributed to the natural gradient of rising O3 concentration with height, exacerbated by the corresponding downstream mountain winds. Our recent field observations corroborate this finding, showing a consistent increase in O3 concentrations by approximately 13.
View Article and Find Full Text PDFProbability density functions for photon propagation in a binary (isotropic-Poisson) statistical mixture with unmatched positive and negative refractive indexes.
Phys Rev E
November 2024
Université Paris-Saclay, CEA, Service d'Études des Réacteurs et de Mathématiques Appliquées, 91191, Gif-sur-Yvette, France.
The exact homogenized probability density function, for a photon making a step of length s has been analytically derived for a binary (isotropic-Poisson) statistical mixture with unmatched refractive indexes. The companions, exact, homogenized probability density functions for a photon to change direction ("scatter"), with polar ϑ and azimuthal φ angles, and the homogenized albedo, have also been obtained analytically. These functions also apply to negative refractive indexes and can reduce the number of Monte Carlo simulations needed for photon propagation in complex binary (isotropic-Poisson) statistical mixtures from hundreds to just one, for an equivalent homogeneous medium.
View Article and Find Full Text PDFHigh albedo daytime radiative cooling for enhanced bifacial PV performance.
Nanophotonics
March 2024
University of Michigan, Ann Arbor, MI, USA.
We present a radiative cooling material capable of enhancing albedo while reducing ground surface temperatures beneath fielded bifacial solar panels. Electrospinning a layer of polyacrylonitrile nanofibers, or nanoPAN, onto a polymer-coated silver mirror yields a total solar reflectance of 99 %, an albedo of 0.96, and a thermal emittance of 0.
View Article and Find Full Text PDFQuantifying the effects of the microphysical hygroscopic restructuring of soot on ensemble optical properties and satellite aerosol optical depth retrievals.
Sci Total Environ
December 2024
Research Centre for Environmental Changes, Academia Sinica, Taipei, Taiwan.
Black carbon, or soot, significantly contributes to atmospheric light absorption due to its low single scattering albedo (SSA). This study investigates the impact of soot's hygroscopic restructuring on satellite remote sensing, focusing on radiative forcing, top-of-atmosphere (TOA) reflectance, and aerosol optical depth (AOD) retrievals. We characterized soot aging using relative humidity (RH) growth factor functions and modeled fresh and aging soot aggregates using a cluster-cluster aggregation algorithm.
View Article and Find Full Text PDFFractional change of scattering and absorbing aerosols contributes to Northern Hemisphere Hadley circulation expansion.
Sci Adv
November 2024
Department of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, P. R. China.
The relative amount of scattering and absorbing aerosols is essential in determining the aerosol radiative and climate effects. Using reanalysis datasets and climate simulations, here, we show that changes in the relative amount of scattering and absorbing aerosols in the Northern Hemisphere (NH) high latitudes, manifested as long-term decreasing trends in aerosol single-scattering albedo (SSA), have played an important role in driving the widening and weakening trends of the NH Hadley circulation (HC) since the early 1980s. Decreasing SSA in the NH middle and high latitudes can notably warm the troposphere there, thus reducing the equator-to-pole temperature gradient, increasing static stability in mid-latitude regions, and leading to the widening and weakening trends of NH HC.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!