Fram Strait Sea Ice Volume Export 1992-2012 from Combined ULS and Satellite Data
Abstract
The Fram Strait between Svalbard and Greenland is the main gateway for sea ice export out of the Arctic Basin. Changes of the sea ice mass balance can either have thermodynamic (melting) or dynamic (export) causes, or a combination of both. Therefore, to better understand the recent decrease in Arctic sea ice volume it is of special importance to monitor changes in the sea ice export. Additionally, inter-annual perturbations in the sea ice transport through Fram Strait can modify the major water mass formation processes in the Greenland Sea and further downstream with consequences for the deep water formation and global ocean circulation. To estimate the sea ice volume export through Fram Strait the three variables sea ice drift, area, and thickness have to be known and combined. The long-term Fram Strait sea ice area export obtained from passive microwave satellite observations since 1982 shows no significant trend. However, for the last decade 2001-2009 a positive trend in sea ice area export can be observed. The sea ice thickness in Fram Strait at 79°N is monitored by Upward Looking Sonars (ULS) since 1990. A newly reprocessed and extended ULS time series for 1990-2011 shows negative ice thickness trends of about 3 and 5 cm per year for the mean and modal ice thickness, respectively, with an increasing negative trend since about 2003. For the combined sea ice volume export some of this reduced ice thickness may compensate the increased ice area export in recent years. We will present an updated Fram Strait sea ice volume export time series for the period 1992 to 2012, combining in-situ ULS ice thickness data with satellite passive microwave observations of sea ice drift and area. Long-term and decadal changes of the ice export are discussed in context with the recent sea ice area and volume decrease in the Arctic Basin.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.C54A..05S
- Keywords:
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- 0750 CRYOSPHERE Sea ice;
- 0762 CRYOSPHERE Mass balance 0764 Energy balance;
- 0758 CRYOSPHERE Remote sensing;
- 4540 OCEANOGRAPHY: PHYSICAL Ice mechanics and air/sea/ice exchange processes