Concentrations and radiative forcing of anthropogenic aerosols from 1750 to 2014 simulated with the Oslo CTM3 and CEDS emission inventory

Geoscientific model development, Journal Year: 2018, Volume and Issue: 11(12), P. 4909 - 4931

Published: Dec. 6, 2018

Abstract. We document the ability of new-generation Oslo chemistry-transport model, CTM3, to accurately simulate present-day aerosol distributions. The model is then used with new Community Emission Data System (CEDS) historical emission inventory provide updated time series anthropogenic concentrations and consequent direct radiative forcing (RFari) from 1750 2014. Overall, CTM3 performs well compared measurements surface remotely sensed optical depth. Concentrations are underestimated in Asia, but higher emissions CEDS than previous inventories result improvements observations. treatment black carbon (BC) scavenging gives better agreement observed vertical BC profiles relative predecessor CTM2. However, Arctic wintertime remain underestimated, a range sensitivity tests indicate that physical understanding processes associated atmospheric processing required simultaneously reproduce both features. Uncertainties input data, resolution, affect distribution all aerosols species, especially at high latitudes altitudes. we find no evidence consistently performance across observables regions baseline configuration. Using CEDS, estimate net RFari 2014 −0.17 W m−2, significantly weaker IPCC AR5 2011–1750 estimate. Differences attributable several factors, including stronger absorption by organic aerosol, parameterization absorption, reduced sulfate cooling. trend towards over recent years more pronounced AR5, illustrating importance capturing regional changes.

Language: Английский

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Measuring light absorption by freshly emitted organic aerosols: optical artifacts in traditional solvent-extraction-based methods

Atmospheric chemistry and physics, Journal Year: 2019, Volume and Issue: 19(13), P. 8817 - 8830

Published: July 11, 2019

Abstract. Recent studies have shown that organic aerosol (OA) could a nontrivial role in atmospheric light absorption at shorter visible wavelengths. Good estimates of OA are therefore necessary to better estimate radiative forcing due these aerosols climate models. One the common techniques used measure is solvent extraction technique from filter samples which involves use spectrophotometer bulk absorbance by solvent-soluble fraction particulate matter. Measured solvent-phase subsequently converted particle-phase coefficient using scaling factors. The conventional view apply correction factor 2 coefficients obtained solvent-extracted based on Mie calculations. appropriate factors function biases incomplete carbon (OC) solvents and size-dependent properties OA. range for along with their potential dependence burn conditions an unexplored area research. Here, we performed comprehensive laboratory study involving three (water, methanol, acetone) investigate bias solvent-extraction-based photometry as compared situ freshly emitted biomass burning. We correlated OC∕TC (total carbon) mass ratio single scattering albedo (SSA) observed conventionally water methanol-extracted might not be extensible all systems, suggest caution while such coefficients. Furthermore, linear correlation between SSA was also established. Finally, spectroscopic data, analyzed differences Ångström exponents (AÅE) solution- particulate-phase measurements. noted AÅE measurements deviate significantly counterparts.

Language: Английский

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Discrepancies between brown carbon light-absorption properties retrieved from online and offline measurements

Aerosol Science and Technology, Journal Year: 2020, Volume and Issue: 55(1), P. 92 - 103

Published: Sept. 11, 2020

We compared the imaginary part of refractive indices (k) brown carbon (BrC) retrieved from online and solvent-extraction offline light-absorption measurements. BrC with variable properties was generated controlled combustion three structurally different fuels: toluene (aromatic), isooctane (branched alkane), cyclohexane (cyclic alkane). The retrieval method involved combining real-time measurements aerosol absorption coefficients (at 422, 532, 781 nm) size distributions Mie calculations. extracting samples two organic solvents, methanol dichloromethane, followed by extracts using a UV-vis spectrophotometer. For least absorbing BrC, k values in both solvents were similar to those aerosol. However, for darker dichloromethane smaller than aerosol, smallest, discrepancy among increasing darkness. These results indicate that produced this study more soluble methanol, solubility decreased Finally, same trend decreasing wavelength dependence as previous data. This further supports brown-black continuum differences observed between are due inefficiency solvent extraction not intrinsic methods.Copyright © 2020 American Association Aerosol Research

Language: Английский

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High rise in carbonaceous aerosols under very low anthropogenic emissions over eastern Himalaya, India: Impact of lockdown for COVID-19 outbreak

Atmospheric Environment, Journal Year: 2020, Volume and Issue: 244, P. 117947 - 117947

Published: Sept. 19, 2020

Language: Английский

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Light absorption of organic carbon emitted from burning wood, charcoal, and kerosene in household cookstoves

Environmental Pollution, Journal Year: 2018, Volume and Issue: 240, P. 60 - 67

Published: May 3, 2018

Language: Английский

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