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Satellite remote sensing of Antarctic sea-ice roughness using scatterometer data
conference contribution
posted on 2023-05-24, 12:40 authored by Alexander FraserAlexander Fraser, Toyota, T, Jansen, PW, Kimura, N, Jan LieserJan Lieser, Guy Williams, Trujillo, E, Leonard, K, Maksym, T, Robert MassomRobert MassomWhile 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.
History
Publication title
International Symposium on Sea Ice in a Changing Environment - Proceedings of the Hobart SymposiumEditors
International Glaciological SocietyPagination
69A779Department/School
Institute for Marine and Antarctic StudiesPublisher
International Glaciological SocietyPlace of publication
Hobart, Tasmania, AustraliaEvent title
International Symposium on Sea Ice in a Changing EnvironmentEvent Venue
Hobart, Tasmania, AustraliaDate of Event (Start Date)
2014-03-10Date of Event (End Date)
2014-03-14Repository Status
- Restricted