Arctic sea ice freeboard from CryoSat-2: Validation using data from the first IceBridge underflight
Abstract
Exact determination of thickness changes in Arctic sea ice is a primary goal of ESA's CryoSat-2 mission. Since its launch on April 8, 2010, CryoSat has collected data to map sea ice thickness and thereby monitor climate-driven ice thickness change. On April 20, 2010 just 12 days after CryoSat's launch - during NASA's IceBridge Spring 2010 campaign, the NASA DC-8 conducted a spatially and temporally coincident survey along some 670 km of a CryoSat ground-track in the northernmost Arctic Ocean. The DC-8 survey was flown out and back along the CryoSat ground-track. The DC-8 collected two laser altimetry datasets: (1) Laser Vegetation Imaging Sensor (LVIS) data, and (2) scanning laser Airborne Topographic Mapper (ATM) data. IceBridge also collected a number of other important data types including digital photography of sea ice, snow thickness radar, Ku-band radar altimetry and gravimetry, which are coincident and nearly simultaneous with SAR-mode Synthetic aperture Interferometric Radar ALtimeter (SIRAL) data collected by CryoSat. LVIS data were collected on the outbound high-altitude (25,000 feet) flight leg while ATM data were collected on the return, low-altitude (1500 feet) flight leg. CryoSat's SIRAL altimeter data are used to retrieve freeboard, i.e., the height of the ice surface above that of the local sea surface (observed in leads). Freeboard can be used to estimate sea ice thickness by assuming the ice is in isostatic equilibrium. In this investigation we compare freeboard retrievals from CryoSat with freeboard estimates derived using IceBridge data. Corrections for snow thickness are applied using IceBridge radar data. Freeboards retrieved using (a) LVIS data and (b) ATM data, are compared with CryoSat freeboard estimates. These two comparisons taken together provide an important assessment of CryoSat's capabilities to precisely map freeboard and thickness change of Arctic sea ice.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.C53F..04C
- Keywords:
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- 0750 CRYOSPHERE / Sea ice;
- 4599 OCEANOGRAPHY: PHYSICAL / General or miscellaneous