Ocean variability contributing to basal melt rate near the i
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TitleOcean variability contributing to basal melt rate near the ice front of Ross Ice Shelf, AntarcticaAbstractBasal melting of ice shelves is an important, but poorly understood, cause of Antarctic ice sheet mass loss and freshwater production. We use data from two moorings deployed through Ross Ice Shelf, 6 and 16 km south of the ice front east of Ross Island, and numerical models to show how the basal melting rate near the ice front depends on sub-ice-shelf ocean variability. The moorings measured water velocity, conductivity, and temperature for 2 months starting in late November 2010. About half of the current velocity variance was due to tides, predominantly diurnal components, with the remainder due to subtidal oscillations with periods of a few days. Subtidal variability was dominated by barotropic currents that were large until mid-December and significantly reduced afterward. Subtidal currents were correlated between moorings but uncorrelated with local winds, suggesting the presence of waves or eddies that may be associated with the abrupt change in water column thickness and strong hydrographic gradients at the ice front. Estimated melt rate was 1.2 ± 0.5 m a-1 at each site during the deployment period, consistent with measured trends in ice surface elevation from GPS time series. The models predicted similar annual-averaged melt rates with a strong annual cycle related to seasonal provision of warm water to the ice base. These results show that accurately modeling the high spatial and temporal ocean variability close to the ice-shelf front is critical to predicting time-dependent and mean values of meltwater production and ice-shelf thinning. Key Points RIS basal melt rates near ice front factor of 10 larger than ice-shelf average Near-ice-front basal melt rates depend similarly on tidal and subtidal currents Modeling predicts maximum near-ice-front basal melt rates in austral summer Copyright 2014. American Geophysical Union. All Rights Reserved.AcknowledgementsThe Woods Hole Oceanographic Institution (WHOI) participation in the ANDRILL Coulman High Program was supported by the National Science Foundation Office of Polar Programs (NSF ANT-0839108) through a subcontract from the University of Nebraska, Lincoln (UNL). This subcontract (UNL 25-0550-0004-004) provided support for R. Limeburner, R. Beardsley, and B. Owens in the planning, field work, and subsequent scientific analysis. I. Arzeno was supported as a 2011 WHOI Summer Student Fellow through the NSF Research Experiences for Undergraduates program (OCE-0649139). L. Padman and S. Springer were supported by NASA grant NNX10AG19G to Earth & Space Research (ESR). M. Williams and C. Stewart were supported by the New Zealand National Institute of Water and Atmosphere (NIWA) core funding under the National Climate Centre, and the Ministry of Business, Innovation, and Employment (Contract CO5X1001). We also wish to acknowledge the following: S. Maas (Victoria University of Wellington) and W. Ostrom (WHOI), for making the field operation successful and safe; S. Fischbein (ANDRILL; UNL) and M. King (U. Tasmania) for providing GPS ice-shelf altitude data collected at M-1 and M-2; C. Laird (Center for Remote Sensing of Ice Sheets, U. Kansas) for providing radar-sensed Ross Ice Shelf thickness near Coulman High; S. Howard (ESR) for help with the ROMS modeling component, with input from the model developer M. Dinniman (Old Dominion University). We greatly appreciate the superb support provided by the ANDRILL Program, the entire Coulman High ice camp community, the NSF Raytheon Polar Services at McMurdo Station, and the Antarctica NZ Scott Base staff. Three anonymous reviewers provided valuable advice that helped us improve this paper. Publication of this paper was funded by the National Science Foundation (OCE-1233598). This is ESR Publication number 151.Funding DetailsOCE-1233598, NSF, National Science Foundation
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1st AuthorArzeno, I.AuthorArzeno, I.Beardsley, R.Limeburner, R.Owens, B.Padman, L.Springer, S.Stewart, C.Williams, M.Year2014JournalJournal of Geophysical Research: OceansVolume119Number7Pages4214-4233DOI10.1002/2014JC009792URLhttps://www.scopus.com/inward/recor.....0b817514a54f350f05a06025bKeywordsMooring, Antarctic ice sheetsBarotropic currentsCurrent velocityDiurnal componentIce shelvesIce surface elevationRoss ice shelvesWater velocities, Ice, air-sea interactionbasal meltingestimation methodice shelfnumerical modelsubtidal environmentwater column, AntarcticaRoss Ice ShelfWest Antarctica, rank5Author Keywords0728 Ice shelves4207 Arctic and Antarctic oceanographyProgrammeK131 - Sea Ice and Southern Ocean Processes
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TypeArticleCitationArzeno, I., Beardsley, R., Limeburner, R., Owens, B., Padman, L., Springer, S., Stewart, C. and Williams, M. (2014). Ocean variability contributing to basal melt rate near the ice front of Ross Ice Shelf, Antarctica. Journal of Geophysical Research: Oceans, 119(7): 4214-4233 IdentifierArzeno2014Relevancerank5
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Williams, M., Ocean variability contributing to basal melt rate near the i , [Arzeno2014]. Antarctica NZ, accessed 28/03/2025, https://adam.antarcticanz.govt.nz/nodes/view/63375, 10.1002/2014JC009792