Dimethyl sulfide and aerosol sulfate in the arctic atmosphere
Date
2011
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Abstract
Dimethyl sulfide (DMS) and its oxidation products, which have been proposed to provide a climate feedback mechanism by affecting aerosol and cloud radiative properties, were measured during onboard sampling campaigns in the Arctic in the Fall of 2007 and 2008. DMS concentrations were found to be localized with highly variable concentrations ranging from below detection limit (0.3 nmol/m3) to 14 nmol/m3. DMS flux was calculated based on surface water measurements conducted in open waters and yielded an average of 0.7 ?mol/m2/d along Baffin Bay. DMS oxidation products, sulfur dioxide (SO2) , methane sulfonic acid (MSA), and sulfate (SO/ -) in aerosols were also measured. Concentrations of atmospheric sulfur compounds during the campaign were [SO2] = 2.7- 135 nmol/m3 (2007) and 0.28-27 nmol/m3 (2008), [MSA] = 0.03-0.07 nmol/m3 (2007) and 0.02-0.14 (2008), and non-seasalt sulfate [nSS-So/-] = 0.5-7.0 nmol/m3 (2007) and 0.01-2.0 nmol/m3 (2008). Median daily biogenic SO2 and so/ - concentrations obtained from stable isotope apportionment techniques were found to be approximately 0-105 nmol/m3 and 0-1. 7 nmol/m3 respectively for 2007 and approximately 0-15 nmol/m3 and 0-0.4 nmol/m3 respectively for 2008. Applying conditions for significant new aerosol formation given in Pirjola et al. (1999), the study shows that sufficient biogenic SO2 is released from DMS oxidation to form new aerosols in clean air conditions. Pre-existing aerosols act as an additional condensation sink that prevents new aerosol formation in air parcels polluted by ship stack emissions. These results suggest that the predicted increase in primary productivity and DMS marine emissions could significantly affect the climate regionally. However, an increase in ship traffic would decrease locally the cooling effect of DMS emissions.
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Bibliography: p. 127-137
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Citation
Rempillo, O. T. (2011). Dimethyl sulfide and aerosol sulfate in the arctic atmosphere (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/4141