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Potential and limitations of marine and ice core sea ice proxies: an example from the Indian Ocean sector


Rothlisberger, R and Crosta, X and Abram, NJ and Armand, LK and Wolff, EW, Potential and limitations of marine and ice core sea ice proxies: an example from the Indian Ocean sector , Quaternary Science Reviews: International Multidisciplinary Review and Research Journal, 29, (1-2) pp. 296-302 . ISSN 0277-3791 (2010) [Refereed Article]

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DOI: doi:10.1016/j.quascirev.2009.10.005


Diatom assemblages in marine cores and sea salt deposition fluxes in ice cores have been used as sea ice proxies in the southern hemisphere. Here, a marine and an ice core proxy record for the Indian Ocean covering the last two glacial cycles are compared in order to illustrate their potential and limitations. The marine core was extracted in a location completely ice free under present-day conditions, and therefore was unable to record changes to the recent sea ice extent. Similarly, no sea ice was recorded at that location during the previous interglacial period. During the last glacial period, however, the site was seasonally covered by sea ice, and the diatom assemblages allowed an estimation of average seasonal sea ice presence. The ice core data originated from the East Antarctic plateau. The marine sodium present in the ice core was used as a proxy of the sea-ice coverage and, on average, a larger sea ice surface led to an increased sea-salt aerosol flux, seen e.g. at the last glacial inception. However, the response of the sea salt flux to increasing sea ice extent diminished during peak glacial conditions when only minimal variability was recorded in the ice core record. A first-order approximation is used to take this non-linear response of the ice core sea ice proxy into account. Based on the ice core proxy record, sea ice extent was reduced considerably during the warm episodes of the previous two interglacial periods compared to modern sea ice extent, in particular during the peak warmth of the Last Interglacial. The ice core proxy also showed a very strong precessional variability (pronounced spectral peak at 23 ka period) over the past 240 ka.

The advantage of combining the two proxy records lies in the complementary nature of their response. While the ice core proxy showed limited sensitivity during full glacial conditions, the marine proxy recorded the seasonal sea-ice coverage. Once the sea ice retreated south of the location of the marine core, the ice core proxy responded to changes in sea ice extent. A composite of marine and ice core records may thus provide a data basis for a more detailed reconstruction of sea ice around Antarctica over the last few glacial–interglacial cycles.

Item Details

Item Type:Refereed Article
Keywords:sea ice, sea salt sodium, diatom, southeast Indian Ocean, EPICA
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Glaciology
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Climate variability (excl. social impacts)
UTAS Author:Armand, LK (Dr Leanne Armand)
ID Code:62421
Year Published:2010
Web of Science® Times Cited:37
Deposited By:Centre for Marine Science
Deposited On:2010-03-12
Last Modified:2015-06-22
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