Sea ice dynamics/thermodynamics observation in the Arctic Ocean
co-pi: Takashi Kikuchi (JAMSTEC)
co-investigators: Petra Heil (U. Tasmania), Andrew Roberts (IARC/ARSC), Ignatius Rigor (U. Washington), Alice Orlich (IARC), Bill Shaw (NPS), Jackie Richter-Menge (CRREL), Jamie Morrison (U. Washington), Hajo Eicken (UAF), Chris Petrich (UAF), Ron Lindsay (U. Washington)
The retreat of Arctic sea ice extent during summer has attracted considerable attention from the public and science communities, especially since the record-shattering minimum set during the summer of 2007.
A significant body of work has been done by others investigating mechanisms behind the recent sea ice retreat. There is general consensus that changes in ice drift pattern, air temperature, and cloud cover (related to changes in atmospheric circulation) are implicated. Changes in ocean circulation may also play a role, and Shimada et al. (2006) hypothesize a mechanism whereby weakening of the ice cover through thinning could lead to enhanced wind stress transfer to the ocean. This enhances intrusion of Pacific summer water into the Beaufort Sea, which leads to further thinning of the ice cover (a positive feedback). In order for this hypothesis to be correct, the sea ice deformation of a thinning ice pack must not act to increase ice pack thickness and strength through ridging. In other words, if deformation is implicated in a negative feedback on mass balance, the negative feedback must be smaller than the positive thermodynamic feedback. Deformation rates throughout the Arctic have been observed to be increasing since 1979 (Rampal et al., 2009). To date, the interaction between sea ice deformation and thermodynamic ice growth and melt has not been quantified. To quantify this relationship, we need to measure the impact of deformation on redistribution and level ice growth and relate this to variability in surface heat and moisture fluxes in summer.
In order to monitor the impact of sea ice deformation (and other mechanisms implicated in ice loss) on mass balance, we need to measure the mass of ice that survives to the end of summer. This requires accurate methods of monitoring ice area and thickness. The design of a sea ice deformation monitoring system relies on accurate deformation products as well as accurate mass balance estimates. Ice extent is well documented each summer. Ice area satellite products, on the other hand, suffer poor accuracy. It is critical that we develop reliable methods to monitor sea ice area, type, and thickness in the summer, and year-round ice deformation rates.
Our objective is to quantify the dynamic-thermodynamic feedback of the Arctic ice pack in recent years. As wintertime ice dynamics precondition the summer ice melt through control of the sea ice thickness distribution, ice dynamics provide a potential negative or positive feedback to sea ice mass balance.
- Recommendations for design of Sea Ice Deformation Monitoring Systems
- Creation of www.iceplan.org
- Comparison of late summer passive microwave and visual ship based ice concentration
- Relationship between Beaufort Sea ice drift and recent ice loss
- Hutchings, J.K. 2009. Arctic Sea-Ice Measurement Campaign Coordination, CliC Newsletter, 13, pp 18, November 2009.
- Hutchings, J.K., C. Petrich, R. Lindsay, A. Roberts, and J. Zhang. 2009. The use of models in the design and interpretation of filed measurements. In Handbook of sea ice Field Research Techniques, Ed. H. Eicken et al.
- Orlich, A. 2009. Personal field logistics. In Handbook of sea ice Field Research Techniques, Ed. H. Eicken et al., University of Alaska Press.
- Hutchings, J.K. P. Heil, A. Steer, and W.D. Hibler III. Sub-synoptic scale spatial variability of sea ice deformation in the western Weddell Sea during early summer, submitted to J. Phys. Oceanogr., under second review Jan. 2010.
- Hutchings, J.K. and I. Rigor. 2010. Role of ice dynamics in anomalous ice conditions in the Beaufort Sea during 2006 and 2007. To be submitted to J. Geophys. Res.
- Hutchings, J.K. 2010. Trends in the Beaufort Sea ice pack deformation. To be submitted to J. Geophys. Res.