HR: 11:20h
AN: C22A-05    [Abstracts]
TI: Co-incident 3D mapping of sea ice surface elevation and ice draft in the Beaufort Sea
AU: * Doble, M J
EM: mjd50@damtp.cam.ac.uk
AF: Dept of Applied Maths and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences Wilberforce Road, Cambridge, CB3 0WA, United Kingdom
AU: Forsberg, R
EM: rf@spacecenter.dk
AF: Alfred Wegener Institute, Bussestrasse 24, Bremerhaven, D-27570, Germany
AU: Haas, C
EM: c.haas@awi.de
AF: Geodynamics Dept., Danish National Space Center, Juliane Mariesvej 30, Copenhagen, DK-2100, Denmark
AU: Hanson, S
EM: sha@spacecenter.dk
AF: Alfred Wegener Institute, Bussestrasse 24, Bremerhaven, D-27570, Germany
AU: Hendriks, S
EM: s.hendriks@awi.de
AF: Geodynamics Dept., Danish National Space Center, Juliane Mariesvej 30, Copenhagen, DK-2100, Denmark
AU: Martin, T
EM: t.martin@awi.de
AF: Geodynamics Dept., Danish National Space Center, Juliane Mariesvej 30, Copenhagen, DK-2100, Denmark
AU: Skourup, H
EM: hsk@spacecenter.dk
AF: Alfred Wegener Institute, Bussestrasse 24, Bremerhaven, D-27570, Germany
AU: Wadhams, P
EM: pw11@cam.ac.uk
AF: Dept of Applied Maths and Theoretical Physics, University of Cambridge, Centre for Mathematical Sciences Wilberforce Road, Cambridge, CB3 0WA, United Kingdom
AB: Co-incident measurements of sea ice freeboard, thickness and draft were made during the Applied Physics Laboratory Ice Station (APLIS), in April 2007. The campaign was the first time that full three-dimensional mapping of sea ice freeboard and sea ice draft have been achieved simultaneously. Freeboard was measured across a swath width of 300 m at 1 m spatial resolution, using a laser profilometer flown aboard a Twin Otter aircraft. Ice draft was measured across a swath width of approximately 80 m at 0.5 m spatial resolution, using a Gavia AUV fitted with a GeoAcoustics phase-measuring swath sonar. Ice thickness was also measured along co-incident tracks using a helicopter-borne electromagnetic sounding instrument (HEM bird). The laser profilometer and AUV-mounted sonar rely on the assumption of isostatic balance when deriving ice thickness estimates from the ice surface and underside profiles, while the HEM bird records both surfaces simultaneously and independently, though averaging over a significant footprint (30 m) for the underside of the ice. Though the extent of the APLIS dataset was limited by the radius of AUV operations, the dataset will significantly improve our understanding of ice volume in deformed ice areas, particularly our understanding of the contribution of ridges and rubble fields to total Arctic ice volume, their isostatic balance and questions of block-scale porosity. The data will serve to better constrain the effects of porosity and footprint on the operational HEM measurements and, conversely, the HEM measurements will allow conclusions about the impact of the isostatic balance assumption on ice thickness estimates derived from mapping of one surface.
DE: 0750 Sea ice (4540)
DE: 0762 Mass balance (1218, 1223)
DE: 1621 Cryospheric change (0776)
DE: 4207 Arctic and Antarctic oceanography (9310, 9315)
SC: Cryosphere [C]
MN: 2007 Fall Meeting