Chemical apportionment of aerosol column optical depth off the mid‐Atlantic coast of the United States

Hegg, D́ean A.; Livingston, J. M.; Hobbs, Peter V.; Novakov, T.; Russell, Philip B.

doi:10.1029/97jd02293

Cited by 226 publications

(165 citation statements)

References 34 publications

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“…Field studies indicate that organic carbon aerosols yield a major contribution to the total aerosol mass (Hegg et al, 1997), but information on their distribution and radiative properties is scarce. For this study, we have now estimated the 1995 radiative forcing due to fossil fuel organic carbon aerosol to !0.09 W m\ for 1995.…”

Section: Direct Ewectmentioning

confidence: 99%

Historical evolution of radiative forcing of climate

Myhre

Myhre²,

Stordal

2001

Atmospheric Environment

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Section: Direct Ewectmentioning

confidence: 99%

Historical evolution of radiative forcing of climate

Myhre

Myhre²,

Stordal

2001

Atmospheric Environment

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“…In the literature several values have been used for this factor. For instance Hegg et al (1997) and Putaud et al (1999) used 1.7 andTurpin andLim (2001) estimated that the value is 1.6 for urban and 2.1 for nonurban aerosols. used the factor 1.8 for water-soluble organic carbon and 1.2 for water-insoluble organic carbon.…”

Section: Chemical Analysesmentioning

confidence: 99%

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site

et al. 2006

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Abstract. Aerosol chemical composition was measured over the Atlantic Ocean in November-December 1999 and at the Finnish Antarctic research station Aboa in January 2000. The concentrations of all anthropogenic aerosol compounds decreased clearly from north to south. An anthropogenic influence was still evident in the middle of the tropical South Atlantic, background values were reached south of Cape Town. Chemical mass apportionment was calculated for high volume filter samples (D p <3µm). North of the equator 70-80% of the aerosol consisted of non-sea-salt species. The contribution of sea salt was ∼25% in the polluted latitudes, >80% in the Southern Ocean, and <10% at Aboa. The contribution of organic carbon was >10% in most samples, also at Aboa. The correlation of biomass-burning-related aerosol components with 210 Pb was very high compared with that between nss calcium and 210 Pb which suggests that 210 Pb is a better tracer for biomass burning than for Saharan dust. The ratio of the two clear tracers for biomass burning, nss potassium and oxalate, was different in European and in African samples, suggesting that this ratio could be used as an indicator of biomass burning type. The concentrations of continentrelated particles decreased exponentially with the distance from Africa. The shortest half-value distance, ∼100 km, was for nss calcium. The half-value distance of particles that are mainly in the submicron particles was ∼700±200 km. The MSA to nss sulfate ratio, R, increased faster than MSA concentration with decreasing anthropogenic influence, indicating that the R increase could largely be explained by the decrease of anthropogenic sulfate.

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“…Examples in the marine environment include NARE-96 (Cowling et al, 1998), ACE-1 (Bates et al, 1998), ACE-2 (Collins et al, 2000a;, and INDOEX (de Reuss et al, 2001). Over coastal and continental locations, following earlier work of Rosen et al (1992), Kim et al (1993a), Gunter et al (1993), Pinnick et al (1993) and Gunter (1994), more elaborate airborne data sets have been acquired in the Arctic (Hegg et al, 1996), in the US mid-Atlantic coastal region (Hegg et al, 1997;Hartley et al, 2000), and over the Los Angeles Basin (Collins et al, 2000b), among others.…”

Section: Introductionmentioning

confidence: 99%

Airborne measurements of aerosol extinction in the lower and middle troposphere over Wyoming, USA

Han

Montague

Snider

2003

Atmospheric Environment

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Particle size distributions, and scattering and absorption coefficients were measured over the Green River basin of Wyoming during the Southwest Wyoming Visibility Study (SWYVIS) in February and March 1996. Eleven flights were carried out, using the Wyoming King Air research aircraft. In the least polluted regions of the planetary boundary layer, particle number densities detected in the diameter range 0.13-3.0 mm were o100 cm À3 . Aloft, in the stable air of the free troposphere, they were generally even lower, often falling to a few tens of particles per cm 3 . Analyses of bulk aerosol filter samples showed that organic carbonaceous material was the dominant chemical component, with sulfate and refractory species being the largest inorganic components. Combining the filter data with separately measured black carbon mass loading values allowed refractive indices for the aerosol to be calculated, so that PCASP measured size distributions could be revised. Characterizing size parameters were obtained by fitting particle populations to bimodal lognormal distributions. Particle size distributions were somewhat broader at higher altitudes so that larger particles made greater contributions to extinction. Optical closure was attempted by comparing scattering and total extinctions computed by Mie theory with the corresponding values derived from the observations. While the calculated and measured single scattering albedo average values were in reasonably good agreement, even though individual pairs of values sometimes differed significantly, computed scattering coefficients often exceeded those derived from the measurements, by an average of 60%. Reasons for this discrepancy are explored, including the possible modification of the size distribution by partial or total volatilization of particles within the nephelometer and its inlet. r

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Chemical apportionment of aerosol column optical depth off the mid‐Atlantic coast of the United States

Cited by 226 publications

References 34 publications

Historical evolution of radiative forcing of climate

Historical evolution of radiative forcing of climate

Chemical composition of boundary layer aerosol over the Atlantic Ocean and at an Antarctic site

Airborne measurements of aerosol extinction in the lower and middle troposphere over Wyoming, USA

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