Effect of absorbing aerosols on global radiation budget

Chýlek, Petr; Wong, J.

doi:10.1029/95gl00800

Cited by 329 publications

(266 citation statements)

References 19 publications

(3 reference statements)

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“…In (3), sec ξ(t, ϕ) is the secant of the solar zenith angle ξ(t, ϕ), β = 0.23 is the upward scattered fraction for the stratospheric sulfate aerosol particles, and δ str a (t)is the stratospheric sulfate aerosol optical thickness. Here we assume, in line with Charlson et al (1991) and Chylek and Wong (1995), that the upscattering fraction β can be assigned a constant value, which corresponds to an average solar zenith angle. The optical thickness is calculated as…”

Section: Stratospheric Aerosol Forcingmentioning

confidence: 99%

Geoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure

et al. 2008

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We use a coupled climate-carbon cycle model of intermediate complexity to investigate scenarios of stratospheric sulfur injections as a measure to compensate for CO 2 -induced global warming. The baseline scenario includes the burning of 5,000 GtC of fossil fuels. A full compensation of CO 2 -induced warming requires a load of about 13 MtS in the stratosphere at the peak of atmospheric CO 2 concentration. Keeping global warming below 2 • C reduces this load to 9 MtS. Compensation of CO 2 forcing by stratospheric aerosols leads to a global reduction in precipitation, warmer winters in the high northern latitudes and cooler summers over northern hemisphere landmasses. The average surface ocean pH decreases by 0.7, reducing the calcifying ability of marine organisms. Because of the millennial persistence of the fossil fuel CO 2 in the atmosphere, high levels of stratospheric aerosol loading would have to continue for thousands of years until CO 2 was removed from the atmosphere. A termination of stratospheric aerosol loading results in abrupt global warming of up to 5 • C within several decades, a vulnerability of the Earth system to technological failure.V. Brovkin (B) · M. Claussen

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Section: Stratospheric Aerosol Forcingmentioning

confidence: 99%

Geoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure

et al. 2008

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“…Atmospheric aerosols play an important role in both global climate and regional weather because of their ability to scatter and absorb solar radiation (Charlson and Wigley 1994;Chylek and Wong 1995). The dominant light-absorbing component of atmospheric aerosols is thought to be black carbon produced from combustion.…”

Section: Introductionmentioning

confidence: 99%

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

Marley¹,

Gaffney²,

Baird³

et al. 2001

Aerosol Science and Technology

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To adequately assess the effects of atmospheric aerosols on climate, their optical constants (scattering and absorption coef cients) must be known. The absorption and scattering coef cients of the aerosols are derived from the real and imaginary parts of the complex refractive index and are dependent on their size and chemical composition. Because aerosol properties vary signi cantly with location, it is dif cult to assign values for the absorption and scattering of solar radiation by aerosols in models of global climate change. This study reports a new method of collecting size-fractionated atmospheric aerosol samples for the purpose of directly measuring their transmission and re ectance spectra followed by the determination of the complex refractive index across the entire atmospherically relevant spectral range. The samples were collected with a modi ed Sierra high-volume cascade impactor with the usual lter collection surfaces replaced with Te on sheets machined to hold quartz (ultraviolet [UV]/visible transparent) and/or silver chloride (infrared transparent) sample collection plates. Re ectance and transmission spectra can be obtained on the aerosol samples directly as a function of wavelength, from 280 nm to 2.5 m, with an integrating sphere coupled to an UV/visible or a Fourier transform infrared (FTIR) spectrophotometer. The effective real and imaginary components of the refractive index of the bulk sample material can then be approximated, as a function of wavelength, from the sample spectra. Preliminary results are presented for carbon soot samples generated in the laboratory and for standard diesel soot samples in the UV/visible spectral range. These are compared to results obtained for size-fractionated atmospheric aerosol samples collected near Pasco, WA, West Mesa, AZ, and Argonne, IL.

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“…SSA and g are the two fundamental parameters necessary to perform calculations of aerosol radiative properties (e.g., Chylek and Wong, 1995).…”

Section: Computation Of Optical Propertiesmentioning

confidence: 99%

Perturbations of the optical properties of mineral dust particles by mixing with black carbon: a numerical simulation study

et al. 2015

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Abstract. Field observations show that individual aerosol particles are a complex mixture of a wide variety of species, reflecting different sources and physico-chemical transformations. The impacts of individual aerosol morphology and mixing characteristics on the Earth system are not yet fully understood. Here we present a sensitivity study on climaterelevant aerosols optical properties to various approximations. Based on aerosol samples collected in various geographical locations, we have observationally constrained size, morphology and mixing, and accordingly simulated, using the discrete dipole approximation model (DDSCAT), optical properties of three aerosols types: (1) bare black carbon (BC) aggregates, (2) bare mineral dust, and (3) an internal mixture of a BC aggregate laying on top of a mineral dust particle, also referred to as polluted dust.DDSCAT predicts optical properties and their spectral dependence consistently with observations for all the studied cases. Predicted values of mass absorption, scattering and extinction coefficients (MAC, MSC, MEC) for bare BC show a weak dependence on the BC aggregate size, while the asymmetry parameter (g) shows the opposite behavior. The simulated optical properties of bare mineral dust present a large variability depending on the modeled dust shape, confirming the limited range of applicability of spheroids over different types and size of mineral dust aerosols, in agreement with previous modeling studies. The polluted dust cases show a strong decrease in MAC values with the increase in dust particle size (for the same BC size) and an increase of the single scattering albedo (SSA). Furthermore, particles with a radius between 180 and 300 nm are characterized by a decrease in SSA values compared to bare dust, in agreement with field observations. This paper demonstrates that observationally constrained DDSCAT simulations allow one to better understand the variability of the measured aerosol optical properties in ambient air and to define benchmark biases due to different approximations in aerosol parametrization.

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Effect of absorbing aerosols on global radiation budget

Cited by 329 publications

References 19 publications

Geoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure

Geoengineering climate by stratospheric sulfur injections: Earth system vulnerability to technological failure

An Empirical Method for the Determination of the Complex Refractive Index of Size-Fractionated Atmospheric Aerosols for Radiative Transfer Calculations

Perturbations of the optical properties of mineral dust particles by mixing with black carbon: a numerical simulation study

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