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Uncertainties in thickness estimates of floating ice when applying buoyancy assumption


Lieser, JL and Galton-Fenzi, B and Roberts, Jason and Massom, RA, Uncertainties in thickness estimates of floating ice when applying buoyancy assumption, International Symposium on Sea Ice in a Changing Environment - Proceedings of the Hobart Symposium, 10-14 March 2014, Hobart, Tasmania, Australia, pp. 69A811. (2014) [Conference Extract]


The largest impediment to accurately measuring changes in ice volume, both of land origin and sea ice, is with uncertainties in ice thickness estimates. Since the satellite era, the extent and seasonality of sea ice and the location and size of ice shelves and icebergs is quite well known; but those satellites provide only a two-dimensional representation of a three-dimensional entity. Surface elevation measurements by air- or space-borne altimeters provide an estimate of the ice or snow–air interface above a reference surface, the freeboard. In the case of floating ice the reference surface is usually the open water surface. Computing the thickness and subsequently volume of floating ice from altimetry data relies critically on the validity of the parameters used when converting surface elevation measurements into ice thickness. The underlying assumption is that ice and ocean are in hydrostatic equilibrium derived from the buoyancy principle first described by Archimedes in ‘On floating bodies’ proposition 5 discovered in 212 B.C. In this study we present a numerical analysis of the most widely used formula to compute ice thickness from freeboard measurements. We are investigating the errors associated with reasonable uncertainty estimates of the parameters of the buoyancy conversion when applied to surface elevation estimates in the Antarctic marine cryosphere.

Item Details

Item Type:Conference Extract
Keywords:ice volume, sea ice, ice thickness estimates
Research Division:Earth Sciences
Research Group:Physical geography and environmental geoscience
Research Field:Physical geography and environmental geoscience not elsewhere classified
Objective Division:Environmental Policy, Climate Change and Natural Hazards
Objective Group:Understanding climate change
Objective Field:Effects of climate change on Antarctic and sub-Antarctic environments (excl. social impacts)
UTAS Author:Lieser, JL (Dr Jan Lieser)
UTAS Author:Galton-Fenzi, B (Dr Ben Galton-Fenzi)
UTAS Author:Roberts, Jason (Dr Jason Roberts)
UTAS Author:Massom, RA (Dr Robert Massom)
ID Code:90785
Year Published:2014
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2014-04-24
Last Modified:2014-04-24

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