scholarly journals Estimation of Biomass Burning Influence on Air Pollution around Beijing from an Aerosol Retrieval Model

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Sonoyo Mukai ◽  
Masayoshi Yasumoto ◽  
Makiko Nakata
Keyword(s):  
Air Pollution ◽  
Radiative Transfer ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Transfer Problem ◽  
Carbonaceous Aerosols ◽  
Retrieval Model ◽  
Anthropogenic Aerosols ◽  
Radiative Transfer Problem ◽  
Aerosol Retrieval

We investigate heavy haze episodes (with dense concentrations of atmospheric aerosols) occurring around Beijing in June, when serious air pollution was detected by both satellite and ground measurements. Aerosol retrieval is achieved by radiative transfer simulation in an Earth atmosphere model. We solve the radiative transfer problem in the case of haze episodes by successive order of scattering. We conclude that air pollution around Beijing in June is mainly due to increased emissions of anthropogenic aerosols and that carbonaceous aerosols from agriculture biomass burning in Southeast Asia also contribute to pollution.

Investigation of atmospheric aerosols over semi-urban and urban areas in Eastern Indo-Gangetic Plain: seasonal variability and source apportionment using PMF

2021 ◽  
Author(s):  
Kanishtha Dubey ◽  
Shubha Verma
Keyword(s):  
Organic Carbon ◽  
Biomass Burning ◽  
Atmospheric Aerosols ◽  
Urban Areas ◽  
Relative Concentration ◽  
Road Dust ◽  
Water Soluble ◽  
Carbonaceous Aerosols ◽  
Gangetic Plain ◽  
Brick Kilns

<p>The study investigates the chemical composition and source of aerosol origin at a semi-urban (Kharagpur–Kgp) and urban (Kolkata–Kol) region during the period February 2015 to January 2016 and September 2010 to August 2011 respectively. Major water-soluble inorganic aerosols (WSII) were determined using Ion chromatography and carbonaceous aerosols (CA) using OC–EC analyser. A multivariate factor analysis Positive Matrix Factorization (PMF) was used in resolving source of aerosols at the study locations. Seasonal analysis of WSII at Kgp and Kol indicated relative dominance of calcium at both the places followed by sodium, chloride, and magnesium ions. Non-sea salt potassium (nss–K<sup>+</sup>), a biomass burning tracer was found higher at Kol than at Kgp. Sum of secondary aerosols sulphate (SO<sub>4</sub><sup>2-</sup>), nitrate (NO<sub>3</sub><sup>-</sup>) and ammonium (NH<sub>4</sub><sup>+</sup>) was higher at Kol than Kgp with relative concentration of SO<sub>4</sub><sup>2-</sup> being higher than NO<sub>3</sub><sup>-</sup> at Kgp which was vice-versa at Kol. Examination of carbonaceous aerosols showed three times higher concentration of organic carbon (OC) than elemental carbon (EC) with monthly mean of OC/EC ratio > 2, indicating likely formation of secondary organic carbon formation. Seasonal influence of biomass burning inferred from nss–K<sup>+</sup> (OC/EC) ratio relationship indicated dissimilarity in seasonality of biomass burning at Kgp (Kol). PMF resolved sources for Kgp constituted of secondary aerosol emissions, biomass burning, fugitive dust, marine aerosols, crustal dust and emissions from brick kilns while for Kol factors constituted of burning of waste, resuspended paved road dust, coal combustion, sea spray aerosols, vehicular emissions and biomass burning.</p>

scholarly journals The 12C/13C Ratio in Interstellar Dark Clouds

1980 ◽  
Vol 87 ◽  
pp. 411-416
Author(s):  
W.H. Mccutcheon ◽  
R. L. Dickman ◽  
W.L.H. Shuter ◽  
R. S. Roger
Keyword(s):  
Radiative Transfer ◽  
Interstellar Medium ◽  
Stellar Evolution ◽  
Transfer Problem ◽  
Abundance Ratio ◽  
Radiative Transfer Problem ◽  
Dark Clouds ◽  
Non Equilibrium

Since 13C is believed to be produced by non-equilibrium CNO processing in stellar evolution (Truran 1977), measurements of the carbon ratio Rc ≡ [12C] / [13C] in the interstellar medium may provide important information on nucleo-synthesis. Commonly, the ratio (N13/N18)LTE ≡ [13CO/C18O]LTE is measured and from this RLTE ≡ [12CO/13CO]LTE is deduced and these values are often identified with Rc. However, this line of reasoning can be misleading for two reasons (Dickman et al. 1979):(1) The difficulty of determining accurate column densities, [13C16O] and [12C18O], because of the complexity of the radiative transfer problem;(2) The possible role of fractionation, whereby RCO ≡ [12CO] / [13CO] does not necessarily reflect the initial atomic abundance ratio RC (Watson et al. 1976, Langer 1977, Liszt 1978).

scholarly journals Discontinuities in numerical radiative transfer

2019 ◽  
Vol 622 ◽  
pp. A162 ◽  
Author(s):  
Gioele Janett
Keyword(s):  
Radiative Transfer ◽  
Transfer Equation ◽  
Radiative Transfer Equation ◽  
Transfer Problem ◽  
Stellar Atmospheres ◽  
Physical Parameters ◽  
Radiative Transfer Problem ◽  
Intermittent Behavior ◽  
High Order Convergence ◽  
Magnetohydrodynamic Simulations

Observations and magnetohydrodynamic simulations of solar and stellar atmospheres reveal an intermittent behavior or steep gradients in physical parameters, such as magnetic field, temperature, and bulk velocities. The numerical solution of the stationary radiative transfer equation is particularly challenging in such situations, because standard numerical methods may perform very inefficiently in the absence of local smoothness. However, a rigorous investigation of the numerical treatment of the radiative transfer equation in discontinuous media is still lacking. The aim of this work is to expose the limitations of standard convergence analyses for this problem and to identify the relevant issues. Moreover, specific numerical tests are performed. These show that discontinuities in the atmospheric physical parameters effectively induce first-order discontinuities in the radiative transfer equation, reducing the accuracy of the solution and thwarting high-order convergence. In addition, a survey of the existing numerical schemes for discontinuous ordinary differential systems and interpolation techniques for discontinuous discrete data is given, evaluating their applicability to the radiative transfer problem.

scholarly journals Comparison of parallel eigensolvers for a discretized radiative transfer problem

PAMM ◽  
2007 ◽  
Vol 7 (1) ◽  
pp. 1022805-1022806 ◽  
Author(s):  
P. B. Vasconcelos ◽  
O. A. Marques
Keyword(s):  
Radiative Transfer ◽  
Transfer Problem ◽  
Radiative Transfer Problem

scholarly journals The 2D continuum radiative transfer problem

2004 ◽  
Vol 417 (3) ◽  
pp. 793-805 ◽  
Author(s):  
I. Pascucci ◽  
S. Wolf ◽  
J. Steinacker ◽  
C. P. Dullemond ◽  
Th. Henning ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Transfer Problem ◽  
Radiative Transfer Problem
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