Gathering Multibeam Bathymetry Aboard Icebreakers
US-Canada Joint Expedition Deploys Healy and Louis S. St-Laurent For Extended Continental Shelf Mapping in Arctic Ocean
By Andrew A. Armstrong Co-Director Joint Hydrographic Center NOAA Office of Coast Survey Durham, New Hampshire Larry A. Mayer Professor and Director Center for Coastal and Ocean Mapping
University of New Hampshire Durham, New Hampshire and David C. Mosher Research Scientist Geological Survey of Canada–Atlantic Natural Resources Canada Dartmouth, Canada
n August and September 2011, the United States and Canada combined resources for a joint ex- tended continental shelf survey in the Arctic Ocean. Article 76 of the Convention on the Law of the Sea details the criteria for establishing the limits of a nation's continental shelf beyond 200 nautical miles from the shoreline. These criteria involve the key data requirements of bathymetry, sub-bottom profiles and deep seismic profiles. Obtaining bathymetry and seismic profiles in the Arctic Ocean presents the challenges of remoteness and ice cover. Vessels, equipment and strategies must be tailored to overcome these difficulties. At some times of the year in certain parts of
(Top) Multibeam swath track line for the 2011 U.S.-Canada joint Arctic Ocean bathymetric mapping expedition overlaid on the international bathymetric chart of the Arctic Ocean.
(Middle) Difference in multibeam echosounder data when Healy was breaking ice in the lead, and when it was following Louis S. St-Laurent near the Sever Spur area.
(Bottom) Multibeam coverage obtained in heavy ice using the fore and aft beam steering technique. (Credits: NOAA)
10 st / OCTOBER 2012 www.sea-technology.com