Using DMS as a model gas for studying air sea gas exchange via eddy covariance

Studies of air-sea gas exchange have been limited by our ability to accurately measure gas fluxes (and thus exchange velocities) on the same time scales as changes in potential controlling factors. Now the use of atmospheric pressure ionization mass spectrometry (APIMS) has made it possible to measure the flux of dimethyl sulfide (DMS) with an accuracy of tens of percent on a time scale of an hour or less. Since wind speed, surface films, wave slope, sea state, and other factors often change on this same time scale, this makes it possible to deduce the impact of the various controlling-factors. We use data from the Eastern Equatorial Pacific and the Sargasso Sea to demonstrate the approach and discuss its limitations.