Microclimate and mass fluxes of debris-laden ice surfaces in

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TitleMicroclimate and mass fluxes of debris-laden ice surfaces in Taylor Valley, AntarcticaAbstractThis study investigates the microclimate and hydrology of debris-laden ice surfaces in the Taylor Valley, Antarctica, in early summer, focusing on the onset of melt. Measurements of energy and mass fluxes were made on an outwash fan and in moraines near the terminus of Taylor Glacier. The surface microclimate was strongly controlled by absorbed solar radiation, with a low albedo of 0.17. Seasonal warming of the substrate led to an abrupt shift in thermal and hydrological patterns as temperatures exceeded freezing point. Within a week the Bowen ratio switched from 2.05 to 0.48 and mass losses to the atmosphere increased four-fold from 0.39 to 1.6 mm d-1. Melt onset also produced complex ground temperature patterns with strong diurnal damping below the freezing front. These patterns were caused by phase changes in the freezing front, coupled with an abundant water supply from local runoff. Of secondary importance to the surface energy balance and mass fluxes was the effect of local winds on boundary layer characteristics. This resulted in larger mass losses during the more turbulent, warmer and drier down-valley flows. â"' 2014 Antarctic Science Ltd.AcknowledgementsAntarctica New Zealand provided funding and all logistical support for this experiment and we are grateful to all who had a hand in obtaining these observations. Analysis and early writing on this manuscript was completed while the lead author was a visiting fellow at Gateway Antarctica, University of Canterbury and we would like to acknowledge the support provided by the director and staff there. We are also grateful for the comprehensive reviews of two anonymous reviewers, whose comments greatly improved the quality of the final manuscript.

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1st AuthorOliphant, A.AuthorOliphant, A.Hindmarsh, R.Cullen, N.Lawson, W.Year2014JournalAntarctic ScienceVolume27Number1Pages85-100DOI10.1017/S0954102014000534URLhttps://www.scopus.com/inward/recor.....bf7361bcdde57db83f26794baKeywordsboundary layerBowen ratioenergy balanceglacial debrisglacial hydrologymicroclimatephase equilibriumsolar radiationwind field, AntarcticaAntarcticaEast AntarcticaMcMurdo Dry ValleysTaylor Valley, rank5Author Keywordsablationevaporationfreezing frontmeltsublimationsurface energy budget

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TypeArticleCitationOliphant, A., Hindmarsh, R., Cullen, N. and Lawson, W. (2014) Microclimate and mass fluxes of debris-laden ice surfaces in Taylor Valley, Antarctica. Antarctic Science, 27(1): 85-100 doi:10.1017/S0954102014000534 IdentifierOliphant2014Relevancerank5