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SEATTLE â€“ The nationâ€™s only operational polar ice breaker, Coast Guard Cutter Healy is scheduled to arrive U.S. Coast Guard Base Seattle, Pier 36, Nov. 10, 2012 at 10 a.m., after an 84-day deployment to the Arctic.
Healy departed Juneau, Alaska Wednesday morning on the final leg of their Arctic West Summer 2012 deployment in the Bering Sea, Chukchi Sea, Beaufort Sea, Amundsen Gulf and Arctic Ocean, conducting three missions to further the nation’s scientific knowledge of the Arctic.
The first science mission was a multiâ€disciplinary investigation to examine the dynamic ecosystem on Hanna Shoal, an area of high biological and exploratory energy significance. Located 80 nautical miles northwest of Barrow, Alaska, and within 40 nautical miles of the Shell exploratory drill sites, the shallow depths of Hanna Shoal contain unusually high standing stocks of biota due to its location at the confluence of Arctic Ocean and Bering Sea currents. During the 17-day mission Healy’s crew conducted 472 individual science casts to collect pelagic and benthic samples in the vicinity of Hanna Shoal. Data collected will establish a baseline standard for physical, chemical, and biologic properties of the region prior to the pending energy exploration nearby.
The focus of the second mission was to collect bathymetric data necessary to delimit the U.S. Extended Continental Shelf. This was the seventh year Healy participated in this mission. In previous cruises, scientists demonstrated that the foot of the continental slope, a key parameter in determining the extent of the continental shelf, extends well north of the Chukchi Cap into Nautilus Basin towards the Alpha/Mendeleev Ridge. For 12 days Healy cut multiple tracklines across the Nautilus Basin, adding scope and detail to the bathymetric maps of the region. In the course of the mapping, a new submarine channel (160 kilometers long and 80 kilometers deep) was discovered in the Nautilus Basin.
During the second half of the mission, five deep dredge casts were conducted to obtain seabed samples to supplement the bathymetric data. By the end of the mission, approximately 20,000 square nautical miles was mapped, increasing the U.S. Arctic mapping coverage by approximately 25 percent.
The ice coverage throughout this mission was much lighter than in previous years; Healy did not encounter the ice pack, which was less than 7/10th ice coverage, until 81 degrees North latitude.
The third science mission focused on the retrieval and deployment of subsurface moorings which included the first-ever subsurface mooring deployed in the Amundsen Gulf, located north of the Northwest Territories, Canada, that measure the physical properties of the Western Arctic Boundary Current. Left in the Arctic year-round, the moorings require annual servicing to recover data and enable continued operation. To supplement the moorings’ data, water column casts were conducted perpendicular to the current at closely spaced intervals to create a cross section of physical and chemical properties. A programmable ocean glider was also deployed to conduct additional water column measurements along the edge of the continental shelf. It was successfully recovered eight days later after travelling 175 nautical miles in the Beaufort Sea.
Healy was commissioned in 2000, and is the nation’s newest and largest U.S. polar icebreaker. The cutter is 420 feet long and has a permanent crew of 81. Its primary mission is scientific support however, as a Coast Guard cutter, Healy is capable of other operations such as search and rescue, ship escort, environmental protection, and the enforcement of laws and treaties in the Polar Regions.
Source:United States Coast Guard
Written by: USCG on Nov 8, 2012.
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