A global modeling study on carbonaceous aerosol microphysical characteristics and radiative forcing

Abstract. Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, cloud-indirect and semi-direct forcing effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative forcing. Our best estimate for net direct and indirect aerosol radiative forcing between 1750 and 2000 is −0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative forcing can vary between −0.32 to −0.75 W/m2 depending on these carbonaceous particle properties at emission. Assuming that sulfates, nitrates and secondary organics form a coating around a black carbon core, rather than forming a uniformly mixed particle, changes the overall net aerosol radiative forcing from negative to positive. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Black carbon absorption is amplified by sulfate and nitrate coatings, but even more strongly by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative forcing when sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to climate benefits.

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Downscaling aerosols and the impact of neglected subgrid processes on direct aerosol radiative forcing for a representative global climate model grid spacing

Journal of Geophysical Research Atmospheres ◽

10.1029/2010jd015480 ◽

2011 ◽

Vol 116 (D13) ◽

Cited By ~ 29

Author(s):

William I. Gustafson ◽

Yun Qian ◽

Jerome D. Fast

Keyword(s):

Radiative Forcing ◽

Climate Model ◽

Global Climate ◽

Global Climate Model ◽

Grid Spacing ◽

Aerosol Radiative Forcing ◽

The Impact ◽

Aerosol Radiative

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The Impact of Changes in Cloud Water pH on Aerosol Radiative Forcing

Geophysical Research Letters ◽

10.1029/2019gl082067 ◽

2019 ◽

Vol 46 (7) ◽

pp. 4039-4048 ◽

Cited By ~ 7

Author(s):

S. T. Turnock ◽

G. W. Mann ◽

M. T. Woodhouse ◽

M. Dalvi ◽

F. M. O'Connor ◽

...

Keyword(s):

Radiative Forcing ◽

Cloud Water ◽

Aerosol Radiative Forcing ◽

Water Ph ◽

The Impact ◽

Aerosol Radiative

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Aerosol radiative forcing due to enhanced black carbon at an urban site in India

Geophysical Research Letters ◽

10.1029/2002gl015826 ◽

2002 ◽

Vol 29 (18) ◽

pp. 27-1-27-4 ◽

Cited By ~ 175

Author(s):

S. Suresh Babu ◽

S. K. Satheesh ◽

K. Krishna Moorthy

Keyword(s):

Black Carbon ◽

Radiative Forcing ◽

Urban Site ◽

Aerosol Radiative Forcing ◽

Aerosol Radiative

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Sensitivity of aerosol radiative effects to different mixing assumptions in the AEROPT 1.0 submodel of the EMAC atmospheric-chemistry–climate model

Geoscientific Model Development ◽

10.5194/gmd-7-2503-2014 ◽

2014 ◽

Vol 7 (5) ◽

pp. 2503-2516 ◽

Cited By ~ 23

Author(s):

K. Klingmüller ◽

B. Steil ◽

C. Brühl ◽

H. Tost ◽

J. Lelieveld

Keyword(s):

Optical Properties ◽

Radiative Transfer ◽

Black Carbon ◽

Atmospheric Chemistry ◽

Radiative Forcing ◽

Climate Model ◽

Mixing Rule ◽

Aerosol Optical Properties ◽

Internal Mixing ◽

Aerosol Radiative

Abstract. The modelling of aerosol radiative forcing is a major cause of uncertainty in the assessment of global and regional atmospheric energy budgets and climate change. One reason is the strong dependence of the aerosol optical properties on the mixing state of aerosol components, such as absorbing black carbon and, predominantly scattering sulfates. Using a new column version of the aerosol optical properties and radiative-transfer code of the ECHAM/MESSy atmospheric-chemistry–climate model (EMAC), we study the radiative transfer applying various mixing states. The aerosol optics code builds on the AEROPT (AERosol OPTical properties) submodel, which assumes homogeneous internal mixing utilising the volume average refractive index mixing rule. We have extended the submodel to additionally account for external mixing, partial external mixing and multilayered particles. Furthermore, we have implemented the volume average dielectric constant and Maxwell Garnett mixing rule. We performed regional case studies considering columns over China, India and Africa, corroborating much stronger absorption by internal than external mixtures. Well-mixed aerosol is a good approximation for particles with a black-carbon core, whereas particles with black carbon at the surface absorb significantly less. Based on a model simulation for the year 2005, we calculate that the global aerosol direct radiative forcing for homogeneous internal mixing differs from that for external mixing by about 0.5 W m−2.

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Radiative forcing estimates of sulfate aerosol in coupled climate-chemistry models with emphasis on the role of the temporal variability

Atmospheric Chemistry and Physics ◽

10.5194/acp-12-5583-2012 ◽

2012 ◽

Vol 12 (12) ◽

pp. 5583-5602 ◽

Cited By ~ 18

Author(s):

C. Déandreis ◽

Y. Balkanski ◽

J. L. Dufresne ◽

A. Cozic

Keyword(s):

Temporal Variability ◽

Radiative Forcing ◽

Climate Model ◽

Circulation Model ◽

Reference Method ◽

Sulfate Aerosol ◽

The Impact ◽

Net Fluxes ◽

Indirect Radiative Forcing ◽

Aerosol Radiative

Abstract. This paper describes the impact on the sulfate aerosol radiative effects of coupling the radiative code of a global circulation model with a chemistry-aerosol module. With this coupling, temporal variations of sulfate aerosol concentrations influence the estimate of aerosol radiative impacts. Effects of this coupling have been assessed on net fluxes, radiative forcing and temperature for the direct and first indirect effects of sulfate. The direct effect respond almost linearly to rapid changes in concentrations whereas the first indirect effect shows a strong non-linearity. In particular, sulfate temporal variability causes a modification of the short wave net fluxes at the top of the atmosphere of +0.24 and +0.22 W m−2 for the present and preindustrial periods, respectively. This change is small compared to the value of the net flux at the top of the atmosphere (about 240 W m−2). The effect is more important in regions with low-level clouds and intermediate sulfate aerosol concentrations (from 0.1 to 0.8 μg (SO4) m−3 in our model). The computation of the aerosol direct radiative forcing is quite straightforward and the temporal variability has little effect on its mean value. In contrast, quantifying the first indirect radiative forcing requires tackling technical issues first. We show that the preindustrial sulfate concentrations have to be calculated with the same meteorological trajectory used for computing the present ones. If this condition is not satisfied, it introduces an error on the estimation of the first indirect radiative forcing. Solutions are proposed to assess radiative forcing properly. In the reference method, the coupling between chemistry and climate results in a global average increase of 8% in the first indirect radiative forcing. This change reaches 50% in the most sensitive regions. However, the reference method is not suited to run long climate simulations. We present other methods that are simpler to implement in a coupled chemistry/climate model and that offer the possibility to assess radiative forcing.

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Aerosol Radiative Forcing and Forcing Efficiency in the UVB for Regions Affected by Saharan and Asian Mineral Dust

Journal of the Atmospheric Sciences ◽

10.1175/2008jas2816.1 ◽

2009 ◽

Vol 66 (4) ◽

pp. 1033-1040 ◽

Cited By ~ 10

Author(s):

O. E. García ◽

A. M. Díaz ◽

F. J. Expósito ◽

J. P. Díaz ◽

A. Redondas ◽

...

Keyword(s):

Aerosol Optical Depth ◽

Optical Depth ◽

Radiative Forcing ◽

Climate Model ◽

Mineral Dust ◽

Global Climate ◽

Global Climate Model ◽

Aerosol Radiative Forcing ◽

Benchmark Database ◽

Aerosol Radiative

Abstract The influence of mineral dust on ultraviolet energy transfer is studied for two different mineralogical origins. The aerosol radiative forcing ΔF and the forcing efficiency at the surface ΔFeff in the range 290–325 nm were estimated in ground-based stations affected by the Saharan and Asian deserts during the dusty seasons. UVB solar measurements were taken from the World Ozone and Ultraviolet Data Center (WOUDC) for four Asian stations (2000–04) and from the Santa Cruz Observatory, Canary Islands (2002–03), under Gobi and Sahara Desert influences, respectively. The Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth at 550 nm was used to characterize the aerosol load τ, whereas the aerosol index provided by the Total Ozone Mapping Spectrometer (TOMS) sensor was employed to identify the mineral dust events. The ΔF is strongly affected by the aerosol load, the values found being comparable in both regions during the dusty seasons. Under those conditions, ΔF values as large as −1.29 ± 0.53 W m−2 (τ550 = 0.48 ± 0.24) and −1.43 ± 0.38 W m−2 (τ550 = 0.54 ± 0.26) were reached under Saharan and Asian dust conditions, respectively. Nevertheless, significant differences have been observed in the aerosol radiative forcing per unit of aerosol optical depth in the slant path, τS. The maximum ΔFeff values associated with dust influences were −1.55 ± 0.20 W m−2 τS550−1 for the Saharan region and −0.95 ± 0.11 W m−2 τS550−1 in the Asian area. These results may be used as a benchmark database for establishing aerosol corrections in UV satellite products or in global climate model estimations.

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The impact of different aerosol properties and types on direct aerosol radiative forcing and efficiency using AERONET version 3

Atmospheric Research ◽

10.1016/j.atmosres.2020.105343 ◽

2020 ◽

pp. 105343

Author(s):

Stavros-Andreas Logothetis ◽

Vasileios Salamalikis ◽

Andreas Kazantzidis

Keyword(s):

Radiative Forcing ◽

Aerosol Radiative Forcing ◽

The Impact ◽

Aerosol Properties ◽

Aerosol Radiative

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Role of black carbon mass size distribution in the direct aerosol radiative forcing

Atmospheric Chemistry and Physics ◽

10.5194/acp-19-13175-2019 ◽

2019 ◽

Vol 19 (20) ◽

pp. 13175-13188 ◽

Cited By ~ 2

Author(s):

Gang Zhao ◽

Jiangchuan Tao ◽

Ye Kuang ◽

Chuanyang Shen ◽

Yingli Yu ◽

...

Keyword(s):

Size Distribution ◽

Black Carbon ◽

Radiative Forcing ◽

Climate Models ◽

Radiative Effects ◽

Aerosol Radiative Forcing ◽

Mass Size Distribution ◽

Mass Size ◽

Mixing States ◽

Aerosol Radiative

Abstract. Large uncertainties exist when estimating radiative effects of ambient black carbon (BC) aerosol. Previous studies about the BC aerosol radiative forcing mainly focus on the BC aerosols' mass concentrations and mixing states, while the effects of BC mass size distribution (BCMSD) were not well considered. In this paper, we developed a method of measuring the BCMSD by using a differential mobility analyzer in tandem with an Aethalometer. A comprehensive method of multiple charging corrections was proposed and implemented in measuring the BCMSD. Good agreement was obtained between the BC mass concentration integrated from this system and that measured in the bulk phase, demonstrating the reliability of our proposed method. Characteristics of the BCMSD and corresponding radiative effects were studied based on a field measurement campaign conducted in the North China Plain by using our own measurement system. Results showed that the BCMSD had two modes and the mean peak diameters of the modes were 150 and 503 nm. The BCMSD of the coarser mode varied significantly under different pollution conditions with peak diameter varying between 430 and 580 nm, which gave rise to significant variation in aerosol bulk optical properties. The direct aerosol radiative forcing was estimated to vary by 8.45 % for different measured BCMSDs of the coarser mode, which shared the same magnitude with the variation associated with assuming different aerosol mixing states (10.5 %). Our study reveals that the BCMSD as well as its mixing state in estimating the direct aerosol radiative forcing matters. Knowledge of the BCMSD should be fully considered in climate models.

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A global modeling study on carbonaceous aerosol microphysical characteristics and radiative effects

Atmospheric Chemistry and Physics ◽

10.5194/acp-10-7439-2010 ◽

2010 ◽

Vol 10 (15) ◽

pp. 7439-7456 ◽

Cited By ~ 119

Author(s):

S. E. Bauer ◽

S. Menon ◽

D. Koch ◽

T. C. Bond ◽

K. Tsigaridis

Keyword(s):

Organic Carbon ◽

Black Carbon ◽

Radiative Flux ◽

Radiative Effects ◽

Carbonaceous Particle ◽

Flux Change ◽

Aerosol Effects ◽

The Impact ◽

Carbon Aerosols ◽

Black Carbon Aerosols

Abstract. Recently, attention has been drawn towards black carbon aerosols as a short-term climate warming mitigation candidate. However the global and regional impacts of the direct, indirect and semi-direct aerosol effects are highly uncertain, due to the complex nature of aerosol evolution and the way that mixed, aged aerosols interact with clouds and radiation. A detailed aerosol microphysical scheme, MATRIX, embedded within the GISS climate model is used in this study to present a quantitative assessment of the impact of microphysical processes involving black carbon, such as emission size distributions and optical properties on aerosol cloud activation and radiative effects. Our best estimate for net direct and indirect aerosol radiative flux change between 1750 and 2000 is −0.56 W/m2. However, the direct and indirect aerosol effects are quite sensitive to the black and organic carbon size distribution and consequential mixing state. The net radiative flux change can vary between −0.32 to −0.75 W/m2 depending on these carbonaceous particle properties at emission. Taking into account internally mixed black carbon particles let us simulate correct aerosol absorption. Absorption of black carbon aerosols is amplified by sulfate and nitrate coatings and, even more strongly, by organic coatings. Black carbon mitigation scenarios generally showed reduced radiative fluxeswhen sources with a large proportion of black carbon, such as diesel, are reduced; however reducing sources with a larger organic carbon component as well, such as bio-fuels, does not necessarily lead to a reduction in positive radiative flux.

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