Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
Clim. Past, 13, 171-184, 2017
http://www.clim-past.net/13/171/2017/
doi:10.5194/cp-13-171-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
27 Feb 2017
Sea-ice-related halogen enrichment at Law Dome, coastal East Antarctica
Paul Vallelonga1, Niccolo Maffezzoli1, Andrew D. Moy2,3, Mark A. J. Curran2,3, Tessa R. Vance3, Ross Edwards4, Gwyn Hughes4, Emily Barker4, Gunnar Spreen5, Alfonso Saiz-Lopez6, J. Pablo Corella6, Carlos A. Cuevas6, and Andrea Spolaor7,8 1Centre for Ice and Climate, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, Copenhagen Ø 2100, Denmark
2Australian Antarctic Division, Channel Highway, Kingston, TAS 7050, Australia
3Antarctic Climate and Ecosystem Cooperative Research Centre, University of Tasmania, Private Bag 80, Hobart, TAS 7001, Australia
4Physics and Astronomy, Curtin University of Technology, Kent St, Bentley, WA 6102, Perth, Australia
5University of Bremen, Institute of Environmental Physics, Otto-Hahn-Allee 1, 28359 Bremen, Germany
6Department of Atmospheric Chemistry and Climate, Institute of Physical Chemistry Rocasolano, CSIC, Serrano 119, 28006 Madrid, Spain
7Ca'Foscari University of Venice, Department of Environmental Sciences, Informatics and Statistics, Via Torino 155, 30170 Venice Mestre, Italy
8Institute for the Dynamics of Environmental Processes, IDPA-CNR, Via Torino 155, 30170 Venice Mestre, Italy
Abstract. The Law Dome site is ideal for the evaluation of sea ice proxies due to its location near to the Antarctic coast, regular and high accumulation throughout the year, an absence of surface melting or remobilization, and minimal multiyear sea ice. We present records of bromine and iodine concentrations and their enrichment beyond seawater compositions and compare these to satellite observations of first-year sea ice area in the 90–130° E sector of the Wilkes coast. Our findings support the results of previous studies of sea ice variability from Law Dome, indicating that Wilkes coast sea ice area is currently at its lowest level since the start of the 20th century. From the Law Dome DSS1213 firn core, 26 years of monthly deposition data indicate that the period of peak bromine enrichment is during austral spring–summer, from November to February. Results from a traverse along the lee (western) side of Law Dome show low levels of sodium and bromine deposition, with the greatest fluxes in the vicinity of the Law Dome summit. Finally, multidecadal variability in iodine enrichment appears well correlated to bromine enrichment, suggesting a common source of variability that may be related to the Interdecadal Pacific Oscillation (IPO).

Citation: Vallelonga, P., Maffezzoli, N., Moy, A. D., Curran, M. A. J., Vance, T. R., Edwards, R., Hughes, G., Barker, E., Spreen, G., Saiz-Lopez, A., Corella, J. P., Cuevas, C. A., and Spolaor, A.: Sea-ice-related halogen enrichment at Law Dome, coastal East Antarctica, Clim. Past, 13, 171-184, doi:10.5194/cp-13-171-2017, 2017.
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We present a study of bromine, iodine and sodium in an ice core from Law Dome, in coastal East Antarctica. We find that bromine and iodine variability at Law Dome is correlated to changes in the area of sea ice along the Law Dome coast as observed by satellite since the early 1970s. These findings are in agreement with a previous study based on MSA and confirm a long-term trend of sea ice decrease for this sector of Antarctica over the 20th century.
We present a study of bromine, iodine and sodium in an ice core from Law Dome, in coastal East...
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