Evolution of mixing state of black carbon particles: Aircraft measurements over the western Pacific in March 2004

Moteki, Nobuhiro; Kondo, Yutaka; Miyazaki, Y.; Takegawa, N.; Komazaki, Yuichi; Kurata, Gakuji; Shirai, Tomoko; Blake, Donald R.; Miyakawa, Takuma; Koike, M.

doi:10.1029/2006gl028943

Cited by 207 publications

(201 citation statements)

References 22 publications

(31 reference statements)

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“…For example, Fig. 2g shows the results for a lognormal BC size distribution with a D m of 175 nm and σ of 1.5, which is almost identical to that observed in outflow from anthropogenic sources in Japan (Moteki et al, 2007;Oshima et al, 2009a). Fitting the results shown in Fig.…”

Section: Bcphobmentioning

confidence: 84%

“…Although these mass concentrations included both BC-containing and BC-free particles, we applied these bulk values to mass concentrations of soluble BC-free particles in our estimates. The variations of the τ values are estimated to be 17-33 days for a size distribution of hydrophobic BC with D m = 175 and σ = 1.5 (Moteki et al, 2007;Oshima et al, 2009a) and soluble BC-free particles with D m = 300 and σ = 2.0 (Whitby, 1978).…”

Section: Appendix a Estimates Of The Time Scale Of Bc Aging Due To Comentioning

confidence: 99%

“…The size distribution of the bare BC particles was represented by a lognormal distribution, which was divided into 40 size sections ranging from 0.0215 µm to 10 µm in MADRID-BC. Mass median diameters (D m ) and geometric standard deviations (σ ) of the bare BC particles were chosen within ranges of those observed in the atmosphere Moteki et al, 2007;Schwarz et al, 2008a, b); namely combinations of D m (100, 125, 150, 175, and 200 nm) and σ (1.5 and 1.8) values were used in this study (Fig. 1).…”

Section: Calculation Of Conversion Rate (1/τ Bc )mentioning

confidence: 99%

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Development of a parameterization of black carbon aging for use in general circulation models

Oshima

Koike

2013

Geosci. Model Dev.

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Abstract.A parameterization of black carbon (BC) aging in the atmosphere is developed for use in general circulation models (GCMs) that separately treat hydrophobic BC and hydrophilic BC modes but do not explicitly calculate the aging processes of BC. The rate of BC aging is expressed as the conversion rate from hydrophobic BC to hydrophilic BC modes (i.e., inverse of the e-folding time of the conversion, 1/τ BC ). In this study, the conversion rates are estimated using results of detailed calculations by a size and mixing state resolved aerosol box model with numerous initial conditions. We introduce a new concept, the hydrophobic-BCmass-normalized coating rate (V BC ), defined as the rate of increase of the mass concentration of condensed materials on hydrophobic BC normalized by the hydrophobic BC mass concentration. Although the conversion rate largely varies depending on the atmospheric conditions and the concentrations of chemical species, we find that the variations of the conversion rate are generally expressed well by a unique function of V BC for given lognormal size distributions of hydrophobic BC. The parameterized conversion rate is expressed as a function of V BC , which enables the representation of diurnal and seasonal variations of the BC aging rate and its spatial differences in polluted and clean air, while other widely used constant conversion rates cannot. Application of our newly developed parameterization to GCMs will provide more reliable estimates of the spatial distribution of BC and its radiative effects at regional and global scales.

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Section: Bcphobmentioning

confidence: 84%

Section: Appendix a Estimates Of The Time Scale Of Bc Aging Due To Comentioning

confidence: 99%

Section: Calculation Of Conversion Rate (1/τ Bc )mentioning

confidence: 99%

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Development of a parameterization of black carbon aging for use in general circulation models

Oshima

Koike

2013

Geosci. Model Dev.

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“…High values for fBC are consistent with more aged rBC particles, and this is due to the various processes in the ambient atmosphere that lead to the formation of coatings. In this study, the time criterion for distinguishing uncoated or thinly-coated rBC and thickly-coated rBC is 2 μs, and this is based on the observed minimum in the bimodal frequency distribution of delay times [29]. The SP2 measurement data are processed for a 1-h average for the later data analysis and discussion.…”

Section: Rbc and Co Measurementsmentioning

confidence: 99%

Characteristics of Black Carbon Aerosol during the Chinese Lunar Year and Weekdays in Xi’an, China

et al. 2015

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Black carbon (BC) aerosol plays an important role in climate forcing. The net radiative effect is strongly dependent on the physical properties of BC particles. A single particle soot photometer and a carbon monoxide analyser were deployed during the Chinese Lunar Year (CLY) and on weekdays at Xi'an, China, to investigate the characteristics of refractory black carbon aerosol (rBC). The rBC mass on weekdays (8.4 μg·m −3 ) exceeds that during the CLY (1.9 μg·m −3 ), presumably due to the lower anthropogenic emissions during the latter. The mass size distribution of rBC shows a primary mode peak at ~205 nm and a small secondary mode peak at ~102-nm volume-equivalent diameter assuming 2 g·cm −3 in void-free density in both sets of samples. More than half of the rBC cores are thickly coated during the CLY (fBC = 57.5%); the percentage is slightly lower (fBC = 48.3%) on weekdays. Diurnal patterns in rBC mass and mixing state differ for the two sampling periods, which are attributed to the distinct anthropogenic activities. The rBC mass and CO mixing ratios are strongly correlated with slopes of 0.0070 and 0.0016 μg·m

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“…The fine and coarse dust particles were highly correlated and had seasonal cycles. In general, black carbon particles are fine and less than 1 m in size (e.g., Moteki et al 2007). As Yasunari et al (2007) discussed, fine dust particles (insoluble particles) in the Mount Wrangell ice core may include black carbon from forest fires in SI and AL.…”

Section: Implication For Dust and Black Carbon Variationsmentioning

confidence: 99%

Origins of Air Masses over an Alaskan Glacier and Implications for Ice Core Studies in the North Pacific Region

Yasunari

Yamazaki

2009

SOLA

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Simulations of 10-day backward trajectories of air masses from Mount Wrangell, an Alaskan ice core site, were calculated for 11 years on a daily basis. Results were analyzed statistically in order to interpret monthly air mass contributions over the ice core site and to discuss implications for ice core studies in the North Pacific Region (NPR).Increases in tropospheric air mass transport from EA in spring suggest favorable transport conditions for Asian dust during this season. The stratospheric air mass (< 300 hPa) over the ice core site increases in winter and that from East Asia (EA) to the North Pacific Ocean in late spring. The tritium peaks observed in the ice core in late spring were discussed in the context of the present results with two possibilities on the time lag of tritium transportation in the stratosphere and the seasonal variations of water vapor amount in the troposphere. Increases in air masses originating from Siberia, Alaska and Canada in summer-fall favor the transport of black carbon due to forest fires over the ice core site. These results allow advanced interpretation of the origin and transport processes of materials in the ice core proxies in the NPR.

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Evolution of mixing state of black carbon particles: Aircraft measurements over the western Pacific in March 2004

Cited by 207 publications

References 22 publications

Development of a parameterization of black carbon aging for use in general circulation models

Development of a parameterization of black carbon aging for use in general circulation models

Characteristics of Black Carbon Aerosol during the Chinese Lunar Year and Weekdays in Xi’an, China

Origins of Air Masses over an Alaskan Glacier and Implications for Ice Core Studies in the North Pacific Region

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