Polar Icebreakers in a Changing World An Assessment of U.S. Needs (2007) / Chapter Skim
Currently Skimming:
7 Icebreaking Environments and Challenges to U.S. Fleet
7 Icebreaking Environments and Challenges to U.S. Fleet
Pages 65-74
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 65... ...
in a large-scale pattern around the Antarctic continent because Distribution and Characteristics of Sea Ice and Icebergs in there are no bays or basins to restrict its movement. In general, the Polar Regions the sea ice in the Weddell and Ross (slightly lesser extent)
|
From page 66... ...
66 FIGURE 7.1 Map of mean differences in ice concentration from the seasonal minima corresponding to (a) the September climatology in the Arctic and (b)
|
From page 67... ...
. The rate of decline of summer minimum ice marginal seas of the Arctic Ocean, where the insulating efextent amounted to almost 8 percent per decade from 1979 fects of a snow cover are typically low and where the amount to 2005 (NSIDC, 2006)
|
From page 68... ...
68 POLAR ICEBREAKERS IN A CHANGING WORLD FIGURE 7.2 Examples of different ice formation and evolution processes, and associated nomencla ture.
|
From page 69... ...
In conjunction raphy and stronger wind regime of the Southern Ocean com- with the temperature, the amount of salt present within a pared to the enclosed Arctic "Mediterranean" seas typically volume of ice determines the bulk porosity and hence ice results in more openings and fewer deformation features in strength. All other factors being equal, Arctic multiyear ice the Antarctic compared to the Arctic, with the exception of has substantially lower salinity (approaching 0 in the uppersome of the sub-Arctic seas, such as the Bering Sea.
|
From page 70... ...
70 POLAR ICEBREAKERS IN A CHANGING WORLD ice coverage or in a sheet of level fast ice, the ship must force centerline (for maximum protection) , poor sea-keeping broken pieces of ice under or onto the adjacent ice cover, or qualities in open water (a regrettable result of the rounded under the ship itself, in order to proceed.
|
From page 72... ...
The difficulty of this task, particularly in challenging ice years, and the use of icebreakers primarily as ice management tools call for an integrated ice management and resupply strategy, ensuring the success of the mission while minimizing the effort expended in high-cost, high-risk icebreaking activities. Key components of such an approach include the following.
|
From page 73... ...
73 ICEBREAKING ENVIRONMENTS AND CHALLENGES TO THE U.S. FLEET ever, on occasion (roughly once every decade)
|
From page 74... ...
. Among other factors, the amount of local resSound that was fostered by the icebergs over the past sev- cue operations (in northern Alaska typically supported by eral years has now reached such substantial thickness that the North Slope Borough's Search and Rescue Operations only a major "centennial" storm is capable of breaking it Center)
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.