Sea salt as an ice core proxy for past sea ice extent: A process-based model study

Levine, J. G. and Yang, X. and Jones, A. E. and Wolff, E. W. (2014) Sea salt as an ice core proxy for past sea ice extent: A process-based model study. Journal of Geophysical Research: Atmospheres, 119 (9). 2013JD020925. ISSN 2169-8996 DOI 10.1002/2013JD020925

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/2013JD0...

Abstract

Sea ice is a reflection of, and a feedback on, the Earth's climate. We explore here, using a global atmospheric chemistry-transport model, the use of sea salt in Antarctic ice cores to obtain continuous long-term, regionally integrated records of past sea ice extent, synchronous with ice core records of climate. The model includes the production, transport, and deposition of sea salt aerosol from the open ocean and “blowing snow” on sea ice. Under current climate conditions, we find that meteorology, not sea ice extent, is the dominant control on the atmospheric concentration of sea salt reaching coastal and continental Antarctic sites on interannual timescales. However, through a series of idealized sensitivity experiments, we demonstrate that sea salt has potential as a proxy for larger changes in sea ice extent (e.g., glacial-interglacial). Treating much of the sea ice under glacial conditions as a source of salty blowing snow, we demonstrate that the increase in sea ice extent alone (without changing the meteorology) could drive, for instance, a 68% increase in atmospheric sea salt concentration at the site of the Dome C ice core, which exhibits an approximate twofold glacial increase in sea salt flux. We also show how the sensitivity of this potential proxy decreases toward glacial sea ice extent—the basis of an explanation previously proposed for the lag observed between changes in sea salt flux and δD (an ice core proxy for air temperature) at glacial terminations. The data thereby permit simultaneous changes in sea ice extent and climate.

Item Type: Article
Uncontrolled Keywords: 2014AREP; IA68;
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
08 - Green Open Access
Journal or Publication Title: Journal of Geophysical Research: Atmospheres
Volume: 119
Page Range: 2013JD020925
Identification Number: 10.1002/2013JD020925
Depositing User: Sarah Humbert
Date Deposited: 25 Aug 2014 23:06
Last Modified: 16 Nov 2014 01:00
URI: http://eprints.esc.cam.ac.uk/id/eprint/3093

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