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Satellite remote sensing of Antarctic sea-ice roughness using scatterometer data

Citation

Fraser, AD and Toyota, T and Jansen, PW and Kimura, N and Lieser, JL and Williams, GD and Trujillo, E and Leonard, K and Maksym, T and Massom, RA, Satellite remote sensing of Antarctic sea-ice roughness using scatterometer data, International Symposium on Sea Ice in a Changing Environment - Proceedings of the Hobart Symposium, 10-14 March 2014, Hobart, Tasmania, Australia, pp. 69A779. (2014) [Conference Extract]

Abstract

While sea-ice concentration is frequently observed from polar orbiting passive microwave satellite instruments, equivalent large-scale information on sea-ice sub-metre-scale roughness is currently unknown. Roughness on this scale is closely related to sea-ice thickness, and has implications for primary productivity near the ice/ocean interface, and flow-on effects for ecosystems. C-band (~5 GHz) off-nadir microwave backscatter strength from sea ice is sensitive to many physical characteristics of the sea ice. During summertime and early autumn, liquid water-related processes dominate backscatter variability (formation of melt water and superimposed ice, snow/ice interface flooding). However, during freezing conditions, backscatter variability reduces in the inner pack, and backscatter becomes more representative of snow/ice interface or air/snow interface roughness (dry snow on the order of 1 m thick is largely transparent at C-band, though experimental results suggest a significant portion of backscatter occurs at the air/snow interface). We demonstrate that EUMETSAT Advanced Scatterometer (ASCAT) C-band scatterometer isotropic roughness data are sensitive to sea-ice roughness. Validation is provided by helicopter-mounted C-band nadir backscatter radar data and lidar swath data acquired in early spring, 2007, during the Australian-led Sea Ice Physics and Ecosystems eXperiment (SIPEX) campaign, and newly-acquired measurements of rugosity and snow/ice interface roughness from Autonomous Underwater Vehicle (AUV)-derived multibeam sonar acquired during the follow-up marine science voyage, SIPEX II. Using high-resolution sea-ice motion vectors from passive microwave imagery, we also investigate the links between large-scale sea-ice convergence and sub-metre-scale roughness.

Item Details

Item Type:Conference Extract
Keywords:Antarctic sea ice, sea ice roughness, sea ice concentration
Research Division:Earth Sciences
Research Group:Geophysics
Research Field:Geophysics not elsewhere classified
Objective Division:Environment
Objective Group:Climate and Climate Change
Objective Field:Climate Variability (excl. Social Impacts)
Author:Fraser, AD (Dr Alex Fraser)
Author:Jansen, PW (Mr Peter Jansen)
Author:Lieser, JL (Dr Jan Lieser)
Author:Williams, GD (Dr Guy Williams)
Author:Massom, RA (Dr Robert Massom)
ID Code:90791
Year Published:2014
Deposited By:CRC-Antarctic Climate & Ecosystems
Deposited On:2014-04-24
Last Modified:2015-11-06
Downloads:0

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