Optical properties and mineralogical composition of different Saharan mineral dust samples: a laboratory study

Linke, Christian; Möhler, Ottmar; Veres, Andreas; Mohácsi, Árpád; Bozóki, Zoltán; Szabó, Gábor; Schnaiter, M.

doi:10.5194/acp-6-3315-2006

Cited by 165 publications

(162 citation statements)

References 16 publications

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“…Contrary to the MAE values, there is no statistically significant size dependence of the AAE values, ranging from 2.5 (±0.2) to 4.1 (±0.3), with an average of 3.3 (±0.7), for the PM 10.6 size fraction and between 2.6 (±0.2) and 5.1 (±0.4), with an average of 3.5 (±0.8), for the PM 2.5 fraction. Our values are in the range of those published in the literature (Fialho et al, 2005;Linke et al, 2006;Müller et al, 2009;Petzold et al, 2009;Yang et al, 2009;Weinzierl et al, 2011;Moosmüller et al, 2012;Denjean et al, 2016b), shown in Table 5. AAE values close to 1.0 are found for urban aerosols where fossil fuel combustion is dominant, while AAE values for brown carbon from incomplete combustion are in the range of 3.5-4.2 (Yang et al, 2009;Chen et al, 2015;Massabò et al, 2016).…”

Section: Spectral and Size Variability Of The Mass Absorption Efficiencysupporting

confidence: 75%

“…The former is lower than the value of 99 × 10 −3 m 2 g −1 that we obtain by extrapolating our measurement at 375 nm. Likewise, our values for the Morocco sample are higher than reported by Linke et al (2006) at 266 and 660 nm. Conversely, the agreement with the estimates of Yang et al (2009) for mineral dust locally re-suspended in Xianghe, near Beijing (China), is very good at all wavelengths between 375 and 880 nm.…”

Section: Spectral and Size Variability Of The Mass Absorption Efficiencycontrasting

confidence: 54%

“…Sahara Morocco 107 (13) 88 (11) 34 (6) 14 (3) 15 (4) 2.6 (0.3) Libya 132 (17) 103 (14) 33 (7) -(-) -(-) 4.1 (0.4) Algeria 95 (9) 71 (11) 37 (7) 12 (5) 12 ( (124) 227 (78) estimates available in the literature Linke et al, 2006;Yang et al, 2009;Denjean et al, 2016b), reported in Table 5. For the China Ulah Buhn sample, Alfaro et al (2004) reported 69.1 × 10 −3 and 9.8 × 10 −3 m 2 g −1 at 325 and 660 nm, respectively.…”

Section: Spectral and Size Variability Of The Mass Absorption Efficiencymentioning

confidence: 99%

“…Balkanski et al (2007) showed that lowering the dust absorption properties to an extent that reconciles them both with the remote-sensing observations and the state of knowledge of the mineralogical composition allowed calculating the clear-sky shortwave radiative effect of dust in agreement with satellite-based observations. A significant number of observations have quantified the shortwave lightabsorbing properties of mineral dust both by direct measurements Linke et al, 2006;Osborne et al, 2008;McConnell et al, 2008;Derimian et al, 2008;Yang et al, 2009;Müller et al, 2009;Petzold et al, 2009;Moosmüller et al, 2012;Wagner et al, 2012;Ryder al., 2013a;Utry et al, 2014;Denjean et al, 2016a, b) and indirectly by quantifying the amount and the speciation of the light-absorbing compounds in mineral dust, principally iron oxides (Lafon et al, , 2006Lazaro et al, 2008;Derimian et al, 2008;Zhang et al, 2008;Kandler et al, 2007Kandler et al, , 2009Kandler et al, , 2011Formenti et al, 2014a, b).…”

Section: Introductionmentioning

confidence: 99%

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Spectral- and size-resolved mass absorption efficiency of mineral dust aerosols in the shortwave spectrum: a simulation chamber study

et al. 2017

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Abstract. This paper presents new laboratory measurements of the mass absorption efficiency (MAE) between 375 and 850 nm for 12 individual samples of mineral dust from different source areas worldwide and in two size classes: PM 10.6 (mass fraction of particles of aerodynamic diameter lower than 10.6 µm) and PM 2.5 (mass fraction of particles of aerodynamic diameter lower than 2.5 µm). The experiments were performed in the CESAM simulation chamber using mineral dust generated from natural parent soils and included optical and gravimetric analyses.The results show that the MAE values are lower for the PM 10.6 mass fraction (range 37-135 × 10 −3 m 2 g −1 at 375 nm) than for the PM 2.5 (range 95-711 × 10 −3 m 2 g −1 at 375 nm) and decrease with increasing wavelength as λ −AAE , where the Ångström absorption exponent (AAE) averages between 3.3 and 3.5, regardless of size. The size independence of AAE suggests that, for a given size distribution, the dust composition did not vary with size for this set of samples. Because of its high atmospheric concentration, light absorption by mineral dust can be competitive with black and brown carbon even during atmospheric transport over heavy polluted regions, when dust concentrations are significantly lower than at emission. The AAE values of mineral dust are higher than for black carbon (∼ 1) but in the same range as light-absorbing organic (brown) carbon. As a result, depending on the environment, there can be some ambiguity in apportioning the aerosol absorption optical depth (AAOD) based on spectral dependence, which is relevant to the development of remote sensing of light-absorbing aerosols and their assimilation in climate models. We suggest that the sample-to-sample variability in our dataset of MAE values is related to regional differences in the mineralogical composition of the parent soils. Particularly in the PM 2.5 fraction, we found a strong linear correlation between the dust lightPublished by Copernicus Publications on behalf of the European Geosciences Union. 7176 L. Caponi et al.: Spectral-and size-resolved mass absorption efficiency of mineral dust aerosols absorption properties and elemental iron rather than the iron oxide fraction, which could ease the application and the validation of climate models that now start to include the representation of the dust composition, as well as for remote sensing of dust absorption in the UV-vis spectral region.

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Section: Spectral and Size Variability Of The Mass Absorption Efficiencysupporting

confidence: 75%

Section: Spectral and Size Variability Of The Mass Absorption Efficiencycontrasting

confidence: 54%

Section: Spectral and Size Variability Of The Mass Absorption Efficiencymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectral- and size-resolved mass absorption efficiency of mineral dust aerosols in the shortwave spectrum: a simulation chamber study

et al. 2017

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“…Assuming a classical density value of 2.5 g cm −3 for spherical dust particles (Dulac et al, 1989;Zender et al, 2003;Linke et al, 2006), V g is thus about 0. 0076, 0.19, 0.76, 3.0, 6.8, and 19 cm s −1 for particles of 1,5,10,20,30, and 50 µm in diameter, respectively, implying a downward transport ranging from about 6.6 to 16 400 m d −1 .…”

Section: Discussion Related To Dust Sedimentationmentioning

confidence: 99%

In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013

et al. 2018

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Parameterizations for narrowband and broadband albedo of pure snow and snow containing mineral dust and black carbon

2015

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The reduction of snow spectral albedo by black carbon (BC) and mineral dust, both alone and in combination, is computed using radiative transfer modeling. Broadband albedo is shown for mass fractions covering the full range from pure snow to pure BC and pure dust, and for snow grain radii from 5 μm to 2500 μm, to cover the range of possible grain sizes on planetary surfaces. Parameterizations are developed for opaque homogeneous snowpacks for three broad bands used in general circulation models and several narrower bands. They are functions of snow grain radius and the mass fraction of BC and/or dust and are valid up to BC content of 10 ppm, needed for highly polluted snow. A change of solar zenith angle can be mimicked by changing grain radius. A given mass fraction of BC causes greater albedo reduction in coarse-grained snow; BC and grain radius can be combined into a single variable to compute the reduction of albedo relative to pure snow. The albedo reduction by BC is less if the snow contains dust, a common situation on mountain glaciers and in agricultural and grazing lands. Measured absorption spectra of mineral dust are critically reviewed as a basis for specifying dust properties for modeling. The effect of dust on snow albedo at visible wavelengths can be represented by an "equivalent BC" amount, scaled down by a factor of about 200. Dust has little effect on the near-IR albedo because the near-IR albedo of pure dust is similar to that of pure snow.

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Optical properties and mineralogical composition of different Saharan mineral dust samples: a laboratory study

Cited by 165 publications

References 16 publications

Spectral- and size-resolved mass absorption efficiency of mineral dust aerosols in the shortwave spectrum: a simulation chamber study

Spectral- and size-resolved mass absorption efficiency of mineral dust aerosols in the shortwave spectrum: a simulation chamber study

In situ measurements of desert dust particles above the western Mediterranean Sea with the balloon-borne Light Optical Aerosol Counter/sizer (LOAC) during the ChArMEx campaign of summer 2013

Parameterizations for narrowband and broadband albedo of pure snow and snow containing mineral dust and black carbon

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