Sea ice growth rates near ice shelves
Details of Research
TitleSea ice growth rates near ice shelvesAbstractSea ice growth rates near ice shelves are influenced by ocean-ice shelf interactions. Sea ice growth rates and ocean observations from McMurdo Sound, Antarctica in 1999 and 2000 are presented in this paper. Growth rate measurements were made for an individual platelet crystal through video camera observations. It was found that the crystal grew in discontinuous, episodic bursts at rates of the order of 10 -6ms -1. Sea water 0.15m beneath the lower ice surface was measured to be supercooled by 0.01K. Indications are that supercooling was continuous over the period of episodic platelet ice crystal growth and the growth bursts are attributed to the influence of variable currents. Growth rates for bulk sea ice (i.e., columnar and incorporated platelet ice) and heat fluxes were derived from ice temperature measurements. The growth rates for bulk sea ice were found to be of the order of 10 -7m s -1, an order of magnitude less than the rates for the individual platelet ice crystal. The residual of the energy balance suggested that a negative oceanic heat flux (i.e., heat transport down into the ocean) occurred, in addition to conduction of heat up into the atmosphere. Both salinity-based growth rate models and an oxygen isotope-based growth rate model (Eicken, 1998) were found to under-predict growth rates compared to those derived from ice temperature measurements. In addition, inverting the growth rates predicted by the models and integrating over the depth of the core failed to accurately predict the date of initial sea ice formation. Modifications are proposed to the models for sea ice formation occurring near ice shelves, where platelet ice formation is likely. Differences between bulk and individual platelet ice crystal growth rates are discussed with reference to heat fluxes, oceanic flows and the Eicken (1998) model. Copyright 2012 Elsevier B.V.AcknowledgementsThe authors thank the Foundation for Research Science and Technology for their ongoing support of Event K131 sea ice research. I.J.S. is grateful to Antarctica New Zealand for awarding her the 1999/2000 Antarctica New Zealand Sir Robin Irvine Post-Graduate Scholarship and for the research opportunities that resulted from it. She also acknowledges the financial support of the University of Otago and a Blair Trust scholarship. Thanks also to Antarctica New Zealand and the Scott Base staff for providing essential field and logistical support. Thanks also to Jeff Scanniello of the United States Antarctic Program Survey Team for discussions on late season sea ice thicknesses. The authors thank Joe Trodahl (Victoria University of Wellington) for providing access to thermistor probe data used in this paper, and appreciated helpful discussions with him and Daniel Pringle related to the analysis of those data. Thanks to Greg Leonard for help with figure production and for discussions on platelet ice formation. Craig Stevens, Mike Williams, Alex Gough, Natalie Robinson, and Andy Mahoney are thanked for their helpful feedback on draft manuscripts. Particular thanks for detailed and thoughtful comments go to two anonymous reviewers, whose very helpful comments were constructive in improving the manuscript.
1st AuthorSmith, I.AuthorSmith, I.Langhorne, P.Frew, R.Vennell, R.Haskell, T.Year2012JournalCold Regions Science and TechnologyVolume83-84Pages57-70DOI10.1016/j.coldregions.2012.06.005URLhttps://www.scopus.com/inward/recor.....1976d70157497ffc03f7e1133KeywordsAntarcticaHeat transportHeat-upIce crystal growthIce crystalsIce formationsIce shelvesIce surfacesOcean observationsOceanic flowOceanic heat fluxOxygen isotopesPlatelet crystalsRate measurementsSea ice formationsSea ice growth, Crystal growthHeat fluxIsotopesOceanographyOxygenPlateletsSea iceSupercoolingTemperature measurement, Growth rate, ice crystalice shelfice-ocean interactionoxygen isotopesea icesupercooling, AntarcticaEast AntarcticaMcMurdo Sound, rank5Author KeywordsIce shelf ocean interactionsOxygen isotopesPlatelet iceSea ice growth ratesSupercoolingProgrammeK131 - Sea Ice and Southern Ocean Processes
TypeArticleCitationSmith, I., Langhorne, P., Frew, R., Vennell, R. and Haskell, T. (2012) Sea ice growth rates near ice shelves. Cold Regions Science and Technology, 83-84: 57-70 doi:10.1016/j.coldregions.2012.06.005
Antarctica NZ (26th Nov 2018). Sea ice growth rates near ice shelves. In Website Antarctica NZ. Retrieved 29th Sep 2020 08:31, from https://adam.antarcticanz.govt.nz/nodes/view/63773