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
Received: 30 Jun 2016 – Discussion started: 13 Jul 2016
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).
Revised: 29 Dec 2016 – Accepted: 10 Feb 2017 – Published: 27 Feb 2017
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.