Exploiting satellite earth observation to quantify current global oceanic DMS flux and its future climate sensitivity

Land, PE; Shutler, J; Bell, TG; Yang, M. 2014 Exploiting satellite earth observation to quantify current global oceanic DMS flux and its future climate sensitivity. Journal of Geophysical Research: Oceans. 10.1002/2014jc010104

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Abstract/Summary

We used coincident Envisat RA2 and AATSR temperature and wind speed data from 2008/2009 to calculate the global net sea-air flux of dimethyl sulfide (DMS), which we estimate to be 19.6 Tg S a21. Our monthly flux calculations are compared to open ocean eddy correlation measurements of DMS flux from 10 recent cruises, with a root mean square difference of 3.1 lmol m22 day21. In a sensitivity analysis, we varied temperature, salinity, surface wind speed, and aqueous DMS concentration, using fixed global changes as well as CMIP5 model output. The range of DMS flux in future climate scenarios is discussed. The CMIP5 model predicts a reduction in surface wind speed and we estimate that this will decrease the global annual sea-air flux of DMS by 22% over 25 years. Concurrent changes in temperature, salinity, and DMS concentration increase the global flux by much smaller amounts. The net effect of all CMIP5 modelled 25 year predictions was a 19% reduction in global DMS flux. 25 year DMS concentration changes had significant regional effects, some positive (Southern Ocean, North Atlantic, Northwest Pacific) and some negative (isolated regions along the Equator and in the Indian Ocean). Using satellite-detected coverage of coccolithophore blooms, our estimate of their contribution to North Atlantic DMS emissions suggests that the coccolithophores contribute only a small percentage of the North Atlantic annual flux estimate, but may be more important in the summertime and in the northeast Atlantic.

Item Type: Publication - Article
Subjects: Chemistry
Computer Science
Data and Information
Ecology and Environment
Marine Sciences
Divisions: Plymouth Marine Laboratory > Science Areas > Cycling in the Sunlit Ocean
Depositing User: Dr Thomas George Bell
Date made live: 22 Dec 2014 11:27
Last Modified: 06 Jun 2017 16:13
URI: http://plymsea.ac.uk/id/eprint/6313

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