Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

Bell, TG; De Bruyn, W; Miller, SD; Ward, B; Christensen, K; Saltzman, ES. 2013 Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed. Atmospheric Chemistry and Physics, 13. 11073-11087. 10.5194/acp-13-11073-2013

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Abstract/Summary

Shipboard measurements of eddy covariance dimethylsulfide (DMS) air–sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s−1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air–sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air–sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions.

Item Type: Publication - Article
Subjects: Atmospheric Sciences
Meteorology and Climatology
Oceanography
Divisions: Plymouth Marine Laboratory > Science Areas > Cycling in the Sunlit Ocean
Depositing User: Dr Thomas George Bell
Date made live: 03 Jun 2014 15:30
Last Modified: 06 Jun 2017 16:11
URI: http://plymsea.ac.uk/id/eprint/5998

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