Dimethyl sulfide is biogenically produced in the surface ocean and oxidizes in the atmosphere to become the major source of both methanesulfonic acid (MSA) and non-sea-salt sulfate (nssSO42-) in the remote marine troposphere. MSA and nssSO42- are lsot from the atmosphere via deposition to the surface and can be measured in ice cores. Ice core observations of MSA concentrations on the East Antarctic Plateau are a factor of 5 to 9 times higher than the last glacial maximum (LGM) compared to modern day, while nssSO42- concentrations are a factor of two higher. In contrast, glacial-interglacial variability of the MSA concentrations in the Siple Dome ice core are of opposite in sign and lower in magnitude. We are utilizing the ICECAP model to investigate possible explanations of the variability in these species, and if MSA might be utilized as a proxy for sea ice and/or biological productivity in the past.
People:
Cecilia Bitz (lead P.I.), Eric Steig (co-P.I.), Becky Alexander (co-P.I.), and Paul Hezel (graduate student)
Funding:
NSF-ANT 0739127
Publications so far:
Hezel, P.J, B. Alexander, C.M. Bitz, E.J. Steig, C.D. Holmes, X. Yang and J. Sciare, Modeled methanesulfonic acid (MSA) deposition in Antarctica and its relationship to sea ice, J. Geophys. Res. 116, D23214, doi:10.1029/2011JF016383 (2011).