|
|
Abstracts
SEARCH Open Science Meeting
October 27, 2003
Seattle, Washington, USA
The Role of Sea Ice in Arctic Coastal Dynamics and Nearshore Processes
Hajo Eicken1, Jerry Brown2, Lee W. Cooper3, T. C. Grenfell4, Kenneth M. Hinkel5, Andrew Mahoney6, James A. Maslanik7, Don K. Perovich8, Craig Tweedie9
1Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, 903 Koyokuk Drive, Fairbanks, AK, 99775, USA, Phone 907-474-7280, Fax 907-474-7290, hajo.eicken@gi.alaska.edu
2International Permafrost Association, PO Box 7, Woods Hole, MA, 02543, USA, Phone 508-457-4982, Fax 508-457-4982, jerrybrown@igc.apc.org
3Department of Ecology & Evolutionary Biology, University of Tennessee, 10515 Research Drive - Room 100, Knoxville, TN, 37932, USA, Phone 865-974-2990, Fax 865-974-7896, lcooper1@utk.edu
4Dept. of Atmospheric Sciences, University of Washington, Box 351640, Seattle, WA, 98135, USA, Phone 206-543-9411, Fax 206-543-0308, tcg@atmos.washington.edu
5Department of Geography, University of Cincinnati, ML 131, Cincinnati, OH, 45221, USA, Phone 513-556-3421, Fax 513-556-3370, kenneth.hinkel@uc.edu
6Geophysical Institute, University of Alaska Fairbanks, PO Box 757320, Fairbanks, AK, 99775, USA, Phone 907-474-5648 , Fax 907-474-7290, mahoney@gi.alaska.edu
7Cooperative Institute for Research in Environmental Sciences, University of Colorado, Campus Box 431 CCAR, Boulder, CO, 80309, USA, Phone 303-492-8974, Fax 303-492-2825, james.maslanik@colorado.edu
8Cold Regions Research & Engineering Laboratory, 72 Lyme Road, Hanover, NH, 03775, USA, Phone 603-646-4255, Fax 603-646-4644, perovich@crrel.usace.army.mil
9Department of Botany & Plant Physiology, Michigan State University, 224 North Kedzie Hall, East Lansing, MI, 48824, USA, Phone 517-355-1284, Fax 517-432-2150, tweedie@msu.edu
The Arctic coastal zone is strongly affected by climate variability and environmental change, with important consequences for marine and terrestrial ecology, coastal infrastructure, and transfer of dissolved and particulate matter from the terrestrial permafrost regime into the marine system. Sea ice plays a key role in mediating and amplifying such environmental changes in the coastal regions. Relevant processes include but are not limited to (1) increased coastline exposure to wave action during summer and fall storms with a receding ice edge, (2) sea-ice entrainment and export of sediments in shallow water environments, (3) direct interaction between sea ice and the seafloor and coastline through gouging and ice push events, (4) impacts of bottom freezing on heat transfer into and out of the submarine permafrost layer, (5) larger scale land-ocean heat and moisture exchange. While the importance of these processes is generally acknowledged, it is currently not at all clear how they quantitatively impact coastal dynamics and nearshore processes, either individually or in concert.
Here, we report on ongoing studies in northern Alaska that are of relevance in this context and could help in developing and refining future research on the role of sea ice for coastal and nearshore processes. On the regional scale, the northward retreat of the summer minimum ice edge in the Chukchi and Beaufort Seas and the lengthening of the open water season during the past decade has had a substantial impact on coastal processes, ranging from increased wave heights and exposure to fall storms to impacts on seabird colonies. These processes play an important role in the evolution of coastal lagoons such as Elson Lagoon at Barrow, which has experienced rapid coastal retreat on the order of 0.5 to 2.5 m/yr. Changes in the open water season are correlated with variations in the large-scale atmospheric circulation patterns (e.g., as expressed in the AO index). In the coastal zone, however, sea-ice changes are more complex and their impact on coastal processes is more difficult to evaluate. Analysis of satellite imagery and onshore studies at Barrow, Alaska indicates that in addition to changes in the length of the ice season, intraannual variability in the stability and morphology of the fast-ice cover has substantially increased. In recent years, apart from a thinning of the ice cover, winter and spring landfast ice break-out events have increased with substantial impacts on ocean-land heat transfer and local subsistence activities. Changes in sea-ice cover are also impacting subsistence hunting activities in Bering Strait communities. Observations of substantial entrainment and export of sediment by sea ice furthermore raise the question whether ice-mediated removal of fine-grained sediments from the shallow shelf may be increasing in importance. For example, comparatively large inventories of cesium-137, a bomb fallout radionuclide associated with fine clay particles, and deposited over the past half-century on the continental shelf, are present in slope, submarine canyon and deep basin sediments close to the continental slope. Changes in sea ice regimes are likely to have other consequences on biogeochemical cycling of biologically important materials in surface Arctic waters, affecting productivity and the rates of transfer.
The characteristic time scales of these processes vary from days to decades, resulting in a complex response of this coupled coastal system to changes in the forcing. We will discuss how activities under the umbrella of SEARCH and other international projects could help in unraveling this puzzle.
Abstract Categories: Coastal Processes
Back to main abstract page
To view the list of records returned in your search you can use your browser's
back button, or perform the same search again:
|
