Dimethyl sulfide in the summertime Arctic atmosphere: measurements and source sensitivity simulations. Mungall, E., L., Croft, B., Lizotte, M., Thomas, J., L., Murphy, J., G., Levasseur, M., Martin, R., V., Wentzell, J., J., B., Liggio, J., & Abbatt, J., P., D. Atmos. Chem. Phys, 16:6665-6680, 2016.
Dimethyl sulfide in the summertime Arctic atmosphere: measurements and source sensitivity simulations [pdf]Paper  Dimethyl sulfide in the summertime Arctic atmosphere: measurements and source sensitivity simulations [link]Website  abstract   bibtex   
Dimethyl sulfide (DMS) plays a major role in the global sulfur cycle. In addition, its atmospheric oxidation products contribute to the formation and growth of atmo-spheric aerosol particles, thereby influencing cloud conden-sation nuclei (CCN) populations and thus cloud formation. The pristine summertime Arctic atmosphere is strongly in-fluenced by DMS. However, atmospheric DMS mixing ratios have only rarely been measured in the summertime Arctic. During July–August, 2014, we conducted the first high time resolution (10 Hz) DMS mixing ratio measurements for the eastern Canadian Archipelago and Baffin Bay as one com-ponent of the Network on Climate and Aerosols: Address-ing Key Uncertainties in Remote Canadian Environments (NETCARE). DMS mixing ratios ranged from below the detection limit of 4 to 1155 pptv (median 186 pptv) during the 21-day shipboard campaign. A transfer velocity param-eterization from the literature coupled with coincident at-mospheric and seawater DMS measurements yielded air–sea DMS flux estimates ranging from 0.02 to 12 µmol m −2 d −1 . Air-mass trajectory analysis using FLEXPART-WRF and sensitivity simulations with the GEOS-Chem chemical trans-port model indicated that local sources (Lancaster Sound and Baffin Bay) were the dominant contributors to the DMS mea-sured along the 21-day ship track, with episodic transport from the Hudson Bay System. After adjusting GEOS-Chem oceanic DMS values in the region to match measurements, GEOS-Chem reproduced the major features of the measured time series but was biased low overall (2–1006 pptv, me-dian 72 pptv), although within the range of uncertainty of the seawater DMS source. However, during some 1–2 day pe-riods the model underpredicted the measurements by more than an order of magnitude. Sensitivity tests indicated that non-marine sources (lakes, biomass burning, melt ponds, and coastal tundra) could make additional episodic contributions to atmospheric DMS in the study region, although local ma-rine sources of DMS dominated. Our results highlight the need for both atmospheric and seawater DMS data sets with greater spatial and temporal resolution, combined with fur-ther investigation of non-marine DMS sources for the Arctic.

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