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  • Southern Ocean  (1)
  • acid deposition  (1)
  • acidic precipitation  (1)
  • aerosol  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Airborne measurements of dimethylsulfide, sulfur dioxide, and aerosol ions over the Southern Ocean South of Australia (1990)
    Springer
    Journal of atmospheric chemistry 10 (1990), S. 341-370 
    Details
    ISSN: 1573-0662
    Keywords: Marine atmosphere ; Southern Ocean ; dimethylsulfide ; sulfur dioxide ; methanesulfonate ; non-sea-salt sulfate ; marine aerosol ; vertical distributions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Vertical distributions of dimethylsulfide (DMS), sulfur dioxide (SO2), aerosol methane-sulfonate (MSA), non-sea-salt sulfate (nss-SO4 2-), and other aerosol ions were measured in maritime air west of Tasmania (Australia) during December 1986. A few cloudwater and rainwater samples were also collected and analyzed for major anions and cations. DMS concentrations in the mixed layer (ML) were typically between 15–60 ppt (parts per trillion, 10−12; 24 ppt=1 nmol m−3 (20°C, 1013 hPa)) and decreased in the free troposphere (FT) to about 〈1–2.4 ppt at 3 km. One profile study showed elevated DMS concentrations at cloud level consistent with turbulent transport (‘cloud pumping’) of air below convective cloud cells. In another case, a diel variation of DMS was observed in the ML. Our data suggest that meteorological rather than photochemical processes were responsible for this behavior. Based on model calculations we estimate a DMS lifetime in the ML of 0.9 days and a DMS sea-to-air flux of 2–3 μmol m−2 d−1. These estimates pertain to early austral summer conditions and southern mid-ocean latitudes. Typical MSA concentrations were 11 ppt in the ML and 4.7–6.8 ppt in the FT. Sulfur-dioxide values were almost constant in the ML and the lower FT within a range of 4–22 ppt between individual flight days. A strong increase of the SO2 concentration in the middle FT (5.3 km) was observed. We estimate the residence time of SO2 in the ML to be about 1 day. Aqueous-phase oxidation in clouds is probably the major removal process for SO2. The corresponding removal rate is estimated to be a factor of 3 larger than the rate of homogeneous oxidation of SO2 by OH. Model calculations suggest that roughly two-thirds of DMS in the ML are converted to SO2 and one-third to MSA. On the other hand, MSA/nss-SO4 2- mole ratios were significantly higher compared to values previously reported for other ocean areas suggesting a relatively higher production of MSA from DMS oxidation over the Southern Ocean. Nss-SO4 2- profiles were mostly parallel to those of MSA, except when air was advected partially from continental areas (Africa, Australia). In contrast to SO2, nss-SO4 2- values decreased significantly in the middle FT. NH4 +/nss-SO4 2- mole ratios indicate that most non-sea-salt sulfate particles in the ML were neutralized by ammonium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00053868
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Chloride and Bromide Loss from Sea-Salt Particles in Southern Ocean Air (1999)
    Springer
    Journal of atmospheric chemistry 33 (1999), S. 299-319 
    Details
    ISSN: 1573-0662
    Keywords: chloride deficit ; bromide deficit ; sea-salt ; aerosol ; Cape Grim
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Geosciences
    Notes: Abstract Datasets on aerosol composition in Southern Ocean air at Cape Grim and Macquarie Island, and rainwater composition at Cape Grim, have been analysed for sea-salt components in order to test the validity of the multiphase autocatalytic halogen activation process proposed initially by Sander and Crutzen (1996) and developed fully for clean marine air by Vogt et al. (1996). Four distinct datasets from the two locations were analysed. All four datasets provided consistent evidence in support of three predictions of the autocatalytic model: (1) overall Cl- deficits in sea-salt aerosol were small, difficult to quantify against analytical uncertainty and at most a few percent; (2) Br- deficits were large, averaging −30% to −50% on an annual basis, with strong seasonality ranging from about −10% in some winter samples to −80% or more in some summer samples; and (3) the Br- and Cl- deficits were clearly linked to the availability of strong, S-acidity in the aerosol, confirming the importance of acid catalysis to the dehalogenation process.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1006120205159
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Wet deposition chemistry studies at Suva, Fiji, a remote tropical island site in the south Pacific (1997)
    Springer
    Environmental geochemistry and health 19 (1997), S. 0-0 
    Details
    ISSN: 1573-2983
    Keywords: wet deposition ; rainwater chemistry ; acidic precipitation ; rainwater ; ion balance
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Medicine
    Notes: Abstract A field project encompassing wet-only rainwater sampling was initiated as a bilateral Fiji/Australia activity. Normally, biweekly samples were collected, using a wet-only rainwater sampler, and analysed for H+, Na+, K+, Mg2+, NH4 +, Cl−, NO3 −, SO4 2−, PO4 3-, methane sulphonic acid, oxalic acid, formic acid and acetic acid. The pH of the rainwater ranged between 5.730 and 4.480 with an average value of 5.176, slightly lower than the pH of unpolluted rainwater saturated with atmospheric CO2(pH = 5.650). Na+and Cl−were the major ions with average concentrations of 98.15 M and 109.57 M respectively. There is an excellent correlation between the cation sum (average 147.71 eq L-1) and the anion sum (average 142.12 eq L-1) attesting to the quality of the data generated. This paper presents the detailed results of the study for a relatively clean remote island site in Suva, Fiji, latitude 18° 09‘ S, longitude 178° 27’ E, height 6 m, and outlines prospects for further work.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1018486002196
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Concentrations of Nitrogen and Sulfur Species in Gas and Rainwater from Six Sites in Indonesia (2000)
    Springer
    Water, air & soil pollution 120 (2000), S. 205-215 
    Details
    ISSN: 1573-2932
    Keywords: acid deposition ; Indonesia ; rainwater chemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Gas mixing ratios of SO2, NO2 and HNO3 and nitrate and sulfate concentrations in rainwater have beenmeasured at six sites in Indonesia. The sites, Jakarta, Serang,Cilegon, Merak and Bogor, in Java, and Bukit Koto Tabang inSumatra, provide a range of pollution regimes in Indonesia.Jakarta and Bogor are heavily polluted sites in Java, whereasBukit Koto Tabang is a clean air station in a relativelyunpopulated area on the west coast of equatorial Sumatra. At thesesites rainwater was collected daily and gas samples weeklyduring 1996. The other three sites Serang, Cilegon and Merakrepresent smaller regional towns in west Java. At these sitesrainwater samples were collected weekly from June 1991 untilJune 1992.The results show that Jakarta has the highest volume-weightedmean sulfate concentrations in rainwater while the lowest weremeasured at Bukit Koto Tabang. Volume-weighted mean nitrateconcentration was about 24 μeq L-1 at Jakarta and Bogor,significantly higher than the 0.8 μeq L-1 measured atBukit Koto Tabang.Sulfur dioxide mixing ratios ranged from 4–7 ppbv in Jakarta toan average of 1.3 ppbv at Bukit Koto Tabang. Nitrogen dioxidemixing ratio was highest in Jakarta averaging 28 ppbv comparedwith the background mixing ratio of 1.2 ppbv at Bukit KotoTabang. Using dry deposition velocities estimated during aseparate study in the similar conditions of Malaysia enabled drydeposition estimates of SO2, HNO3 and NO2.Results of estimated total acidic S and N deposition (wet anddry) were greater than 250 meq m-2 yr-1 at the Jakartaand Bogor sites compared with about 23 meq m-2 yr-1 atBukit Koto Tabang. At Jakarta and Bogor dry deposition accountedfor more than 50% of the total deposition estimates compared with about 20% at Bukit Koto Tabang. Such deposition rates arehigh when compared to critical loads estimated for Indonesia bythe RAINS-Asia model. In this model, critical loads in western Java and equatorial western Sumatra fall into one of twoclasses: 50–100 and 20–50 meq m-2 yr-1. Thus acidic deposition flux at Jakarta and Bogor wasfound to be above the predicted critical loads even for the moreacid insensitive soils.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1005223124903
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    Paper (German National Licenses)
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