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Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 8757-8770, 2017
https://doi.org/10.5194/acp-17-8757-2017
© Author(s) 2017. This work is distributed under
the Creative Commons Attribution 3.0 License.
Research article
18 Jul 2017
Boundary layer and free-tropospheric dimethyl sulfide in the Arctic spring and summer
Roghayeh Ghahremaninezhad1,9, Ann-Lise Norman1, Betty Croft2, Randall V. Martin2, Jeffrey R. Pierce3, Julia Burkart4, Ofelia Rempillo1, Heiko Bozem5, Daniel Kunkel5, Jennie L. Thomas6, Amir A. Aliabadi7, Gregory R. Wentworth4, Maurice Levasseur8, Ralf M. Staebler9, Sangeeta Sharma9, and W. Richard Leaitch9 1Department of Physics and Astronomy, University of Calgary, Calgary, Canada
2Department of Physics and Atmospheric Science, Dalhousie University, Halifax, Canada
3Department of Atmospheric Science, Colorado State University, Fort Collins, USA
4Department of Chemistry, University of Toronto, Toronto, Canada
5Institute of Atmospheric Physics, University of Mainz, Mainz, Germany
6Sorbonne Universités, UPMC Univ. Paris 06, Université Versailles St-Quentin, CNRS/INSU, UMR8190, LATMOS-IPSL, Paris, France
7Environmental Engineering Program, School of Engineering, University of Guelph, Guelph, Canada
8Department of Biology, Laval University, Québec, Canada
9Environment and Climate Change Canada, Toronto, Canada
Abstract. Vertical distributions of atmospheric dimethyl sulfide (DMS(g)) were sampled aboard the research aircraft Polar 6 near Lancaster Sound, Nunavut, Canada, in July 2014 and on pan-Arctic flights in April 2015 that started from Longyearbyen, Spitzbergen, and passed through Alert and Eureka, Nunavut, and Inuvik, Northwest Territories. Larger mean DMS(g) mixing ratios were present during April 2015 (campaign mean of 116  ±  8 pptv) compared to July 2014 (campaign mean of 20  ±  6 pptv). During July 2014, the largest mixing ratios were found near the surface over the ice edge and open water. DMS(g) mixing ratios decreased with altitude up to about 3 km. During April 2015, profiles of DMS(g) were more uniform with height and some profiles showed an increase with altitude. DMS reached as high as 100 pptv near 2500 m.

Relative to the observation averages, GEOS-Chem (www.geos-chem.org) chemical transport model simulations were higher during July and lower during April. Based on the simulations, more than 90 % of the July DMS(g) below 2 km and more than 90 % of the April DMS(g) originated from Arctic seawater (north of 66° N). During April, 60 % of the DMS(g), between 500 and 3000 m originated from Arctic seawater. During July 2014, FLEXPART (FLEXible PARTicle dispersion model) simulations locate the sampled air mass over Baffin Bay and the Canadian Arctic Archipelago 4 days back from the observations. During April 2015, the locations of the air masses 4 days back from sampling were varied: Baffin Bay/Canadian Archipelago, the Arctic Ocean, Greenland and the Pacific Ocean. Our results highlight the role of open water below the flight as the source of DMS(g) during July 2014 and the influence of long-range transport (LRT) of DMS(g) from further afield in the Arctic above 2500 m during April 2015.


Citation: Ghahremaninezhad, R., Norman, A.-L., Croft, B., Martin, R. V., Pierce, J. R., Burkart, J., Rempillo, O., Bozem, H., Kunkel, D., Thomas, J. L., Aliabadi, A. A., Wentworth, G. R., Levasseur, M., Staebler, R. M., Sharma, S., and Leaitch, W. R.: Boundary layer and free-tropospheric dimethyl sulfide in the Arctic spring and summer, Atmos. Chem. Phys., 17, 8757-8770, https://doi.org/10.5194/acp-17-8757-2017, 2017.
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Short summary
We present spring and summertime vertical profile measurements of Arctic dimethyl sulfide (DMS), together with model simulations to consider what these profiles indicate about DMS sources and lifetimes in the Arctic. Our results highlight the role of local open water as the source of DMS(g) during July 2014 and the influence of long-range transport of DMS(g) from further afield in the Arctic during April 2015.
We present spring and summertime vertical profile measurements of Arctic dimethyl sulfide (DMS),...
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