Particle characterization at the Cape Verde atmospheric observatory during the 2007 RHaMBLe intensive

Müller, Konrad; Lehmann, Stefan; Pinxteren, Dominik van; Gnauk, T.; Niedermeier, N.; Wiedensohler, Alfred; Herrmann, Hartmut

doi:10.5194/acp-10-2709-2010

Cited by 71 publications

(64 citation statements)

References 58 publications

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“…The solution was left to evaporate at about 100 • C and thereafter the substrates containing the particles on the foils were measured. As reported by Müller et al (2010), the cut foil diameters were typically 6 mm and were close to the TXRF beam diameter of 10 mm. However, due to sample orientation on the substrate, samples were measured at two different angles having a difference of 90 • between them in order to ensure a complete excitation of the particle spots.…”

Section: Metal Analysismentioning

confidence: 70%

Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde islands

et al. 2013

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Size-resolved trace metal concentrations of 15 elements in aerosol particles at the Cape Verde Atmospheric Observatory (CVAO) under remote background conditions were investigated through analysis of aerosol samples collected during intensive field studies from January 2007 to November 2011 using total reflection x-ray fluorescence (TXRF). The identification of the main air mass origin that influence remote marine aerosol in the northern tropical Atlantic has been investigated. In total, 317 samples were collected. The dataset was analyzed according to the main air mass inflow at the station. We found that remote conditions make up about 45% of the meteorological conditions in a year at CVAO and thus the northern tropical Atlantic. Surprisingly, air masses from North America are often responsible for higher trace metal concentrations in this region.

Elements such as Zn, Pb, Cu, Cr, Ni, and V were mostly found in the submicron size fractions, while elements with dominant crustal or oceanic origin such as Fe, Ti, Mn, Sr, and Rb were found in the coarse fractions (>1 μm). The highest metal concentrations, especially for Zn (3.23 ng m⁻³), Cu (0.81 ng m⁻³), Sr (2.63 ng m⁻³), and Cr (0.53 ng m⁻³), were observed in air masses originating from North America and the concentrations were within the same concentration range to those reported previously in the literature for remote marine aerosols. Fe (12.26 ng m⁻³), Ti (0.91 ng m⁻³), and Mn (0.35 ng m⁻³) showed higher concentrations when air mass came from Europe and the Canary Islands. Pb concentration was low (<0.20 ng m⁻³) and did not vary significantly with air mass direction. The low Pb concentration is indicative of the complete phase-out of leaded gasoline even in African countries. Crustal enrichment factor values decreased from fine to coarse-mode particles with low values (<4) observed for Fe, Mn, and Rb, and high values (>20) for Zn, Cu, Ni, Cr, Pb, and Se. The observed enrichment of the elements was attributed to crustal, marine, anthropogenic, and biogenic sources, as well as long-range transport and resuspension. Zn, Cu and Pb were indicators of anthropogenic activities, while Ti and Sr were indicators of crustal and marine origin, respectively. Oceanic and biogenic emissions might have contributed to most of the Se observed. This work provides the first long-term size-resolved trace metals study for remote tropical northern Atlantic marine aerosols and the dataset could serve as good initiation of yearly flux estimates

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Section: Metal Analysismentioning

confidence: 70%

Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde islands

et al. 2013

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“…Clearly, in the atmosphere, spatial and temporal variations in DF could have a significant impact on the observed BrO distribution. In a recent application of the model to the tropical Atlantic (O'Brien et al, 2009), the model failed to reproduce the high BrO (2-3 ppbv) observed there, which could be partly explained by the low DF used in the model, as recent observation indicates that the sea salt bromine near Cape Verde is heavily depleted (Müller et al, 2010). It is clearly necessary to work towards including a detailed sea salt microphysical-chemical module to study bromine chemistry at the global scale.…”

Section: Results and Analysismentioning

confidence: 99%

Snow-sourced bromine and its implications for polar tropospheric ozone

et al. 2010

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Abstract. In the last two decades, significant depletion of boundary layer ozone (ozone depletion events, ODEs) has been observed in both Arctic and Antarctic spring. ODEs are attributed to catalytic destruction by bromine radicals (Br plus BrO), especially during bromine explosion events (BEs), when high concentrations of BrO periodically occur. However, neither the exact source of bromine nor the mechanism for sustaining the observed high BrO concentrations is completely understood. Here, by considering the production of sea salt aerosol from snow lying on sea ice during blowing snow events and the subsequent release of bromine, we successfully simulate the BEs using a global chemistry transport model. We find that heterogeneous reactions play an important role in sustaining a high fraction of the total inorganic bromine as BrO. We also find that emissions of bromine associated with blowing snow contribute significantly to BrO at mid-latitudes. Modeled tropospheric BrO columns generally compare well with the tropospheric BrO columns retrieved from the GOME satellite instrument (Global Ozone Monitoring Experiment). The additional blowing snow bromine source, identified here, reduces modeled high latitude lower tropospheric ozone amounts by up to an average 8% in polar spring.

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“…Additionally, it was assumed that 10-15 % of the total mass was water. Weighing and the chemical analyses of the impactor samples were carried out according to the methods described in Müller et al (2010). The foils were stored in a refrigerator and transportation was done using cryogenic boxes below −10 • C to avoid chemical processing of organic material.…”

Section: Mass Concentration Using the Gravimetrical Methods (M Gr )mentioning

confidence: 99%

Mass deposition fluxes of Saharan mineral dust to the tropical northeast Atlantic Ocean: an intercomparison of methods

et al. 2014

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Abstract. Mass deposition fluxes of mineral dust to the tropical northeast Atlantic Ocean were determined within this study. In the framework of SOPRAN (Surface Ocean Processes in the Anthropocene), the interaction between the atmosphere and the ocean in terms of material exchange were investigated at the Cape Verde atmospheric observatory (CVAO) on the island Sao Vicente for January 2009. Five different methods were applied to estimate the deposition flux, using different meteorological and physical measurements, remote sensing, and regional dust transport simulations. The set of observations comprises micrometeorological measurements with an ultra-sonic anemometer and profile measurements using 2-D anemometers at two different heights, and microphysical measurements of the sizeresolved mass concentrations of mineral dust. In addition, the total mass concentration of mineral dust was derived from absorption photometer observations and passive sampling. The regional dust model COSMO-MUSCAT was used for simulations of dust emission and transport, including dry and wet deposition processes. This model was used as it describes the AOD's and mass concentrations realistic compared to the measurements and because it was run for the time period of the measurements. The four observation-based methods yield a monthly average deposition flux of mineral dust of 12-29 ng m −2 s −1 . The simulation results come close to the upper range of the measurements with an average value of 47 ng m −2 s −1 . It is shown that the mass deposition flux of mineral dust obtained by the combination of micrometeorological (ultra-sonic anemometer) and microphysical measurements (particle mass size distribution of mineral dust) is difficult to compare to modeled mass deposition fluxes when the mineral dust is inhomogeneously distributed over the investigated area.

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Particle characterization at the Cape Verde atmospheric observatory during the 2007 RHaMBLe intensive

Cited by 71 publications

References 58 publications

Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde islands

Aerosol size-resolved trace metal composition in remote northern tropical Atlantic marine environment: case study Cape Verde islands

Snow-sourced bromine and its implications for polar tropospheric ozone

Mass deposition fluxes of Saharan mineral dust to the tropical northeast Atlantic Ocean: an intercomparison of methods

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