Arctic Ocean Research and Supporting Facilities National Needs and Goals (1995) / Chapter Skim
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2 SCIENTIFIC OBJECTIVES FOR ARCTIC RESEARCH
2 SCIENTIFIC OBJECTIVES FOR ARCTIC RESEARCH
Pages 13-38
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From page 13... ...
· the geology and history of the ocean basin and surrounding continental · world ocean circulation, affecting climate and global change; · chemical tracer and pollution studies; and · life histories of arctic species and food web structure of arctic commu In this chapter, priorities for marine sciences in the Arctic are presented in each of four subdisciplines: marine geology and geophysics, physical science, chemical oceanography, and biological science. Platforms needed for major scientific tasks are described.
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From page 14... ...
and the role of northern regions in affecting the global climate system. Paleoclimatic and paleoceanographic data establishing past conditions must be used to test and validate climate model performance, yet the largest and most critical gap in global data is in the arctic region.
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From page 15... ...
Selection of the best specific drill sites must be preceded by geophysical surveys that include swath mapping of bottom topography and seismic reflection profiling of subseafloor structure. In shallow slope and shelf areas multichannel seismic surveys are required, whereas in the deeper basins single-channel seis · rim.
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From page 16... ...
Tectonic Evolution of the Amerasia Basin The Amerasia Basin is a large area of the world ocean for which useful, testable plate tectonic models are lacking. Until the location and kinematics of the several plates suspected to underlie the basin are established, the origin and tectonic assembly of the surrounding continents and extensive continental shelves will remain poorly understood.
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From page 17... ...
Facilities Requirements Most of the objectives of marine geology and geophysics research do not require year-round access to the Arctic Ocean but could instead be pursued in summer when the ice cover is thinnest. An ARV could be used for swath mapping and for gravity, magnetic, and seismic surveys.
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From page 18... ...
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From page 19... ...
A research icebreaker could provide a surface platform in the margins of the Arctic Ocean during the summer season but would have to be escorted by an icebreaker that could navigate multiyear ice to work in the central Arctic Ocean. Alternatively, if an SSN can be used to conduct underway geophysical mapping, additional station work in the central Arctic could be done from ice camps.
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From page 20... ...
Each of these approaches has different facilities requirements related to the location, time, and space scales to be sampled. Circulation, Mixing, and Water Mass Transformations Model simulations of global change that include ocean-atmosphere-land-ice interactions predict a particularly large increase of surface air temperature and marked reduction of sea ice cover over the Arctic Ocean in response to perturbations such as increased CO2 concentration in the atmosphere (Manatee and Stouffer, 1994~.
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From page 21... ...
An event that began in the late 1960s with a pulse of fresh water into the ocean north of Iceland illustrates how sustained changes in relatively small ocean regions can conceivably change the thermohaline circulation of the Arctic Ocean. This Great Salinity Anomaly" circulated around the Atlantic Ocean and returned to the Greenland Sea via the Atlantic Water inflow through the FaeroeShetland Channel, where it stopped deep water formation (Dickson et al., 1988; Aagaard and Carmack, 1989~.
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From page 22... ...
Surface Energy Balance, Atmospheric Radiation, and Clouds The radiation balance dominates the energy budget of the Arctic Ocean's surface in all seasons, and also plays a major role in the climate feedbacks exhibited by global climate models. These feedbacks involve strong interactions between surface radiative fluxes and the energy and mass balance of the sea ice and snow cover.
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From page 23... ...
The types of data needed include atmospheric moisture flux into the basin, river runoff, mass balance of sea ice, and changes of the water mass characteristics of the Arctic Ocean and tWalter Tucker, U.S. Army Cold Regions Research and Engineering Laboratory, personal communication to committee, February 22, 1995.
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From page 24... ...
The baseline assessment of the circulation requires large-scale surveys of hydrographic variables, chemical tracers, velocity profiles, acoustic travel times, sea ice, and other properties. The primary platforms for the baseline surveys of properties below the arctic halocline are research vessels, which might include the arctic icebreakers and submarines.
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From page 26... ...
The above-mentioned four primary areas of chemical oceanographic research are discussed individually in more detail below. Biogeochemical Cycles The arctic region is not a major producer of biogenic material when compared with the world oceans (probably accounting for less than 10 percent of the total marine primary production)
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From page 27... ...
Water Mass Formation and Circulation Understanding the freshwater balance in the Arctic is important because it affects the density structure in the pyres of the Greenland and Labrador Seas, both of which form dense waters contributing to the global thermohaline circulation. In addition, many of the pollutants released into the Arctic have a riverine source, and consequently the trajectory of the fresh water is an important consideration in assessing the dispersal and fate of these materials.
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From page 28... ...
Because approximately half of the world ocean's abyssal waters originate in and around the Arctic, the importance of understanding deep water formation in the Arctic cannot be overemphasized. A recent analysis of tritium/helium 3 and CFC tracers has indicated a considerable slowdown in the formation of Greenland Sea Deep Water during the 1980s (Schlosser et al., 1991~.
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From page 29... ...
An icebreaking research vessel is the most versatile platform from which to conduct the necessary field operations for chemical oceanography research priorities. This platform is essential because it permits a variety of sampling requirements to be carried out, including collection of water column profiles of dissolved and suspended chemical species, large-volume sampling and processing of trace metals and isotopes, coring, and deployment and recovery of instru
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From page 30... ...
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From page 31... ...
in a more or less time-series mode. However, the movement of ice camps with drifting surface ice may be decoupled from movement of bottom waters (which may move in different directions and at different speeds than the surface currents)
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From page 32... ...
Whatever the cause, the discrepancy suggests that the continental shelves and central Arctic may be decoupled in their carbon production and use. In particular, the central Arctic may uniquely depend on the microbial food web as a link between primary production and higher trophic levels.
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From page 33... ...
The Bering Sea is the location of one of the world's richest fisheries, although various important commercial fish species have declined over the past few decades (NRC, 1995~. Protective management of Bering Sea fisheries may depend on an understanding of the underlying trophic structure of the commercially valuable fish species throughout all seasons, including the ice-covered winter months (NRC, 1995~.
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From page 34... ...
Although a research icebreaker can provide a comprehensive platform for most biological oceanographic field requirements in the Arctic, some of these needs can be met, at least in part, by platforms other than a surface research icebreaker. If sufficient equipment and personnel can be transported, ice camps may provide opportunities for temporal studies at a single location.
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From page 36... ...
Some types of research would require a research icebreaker; some could use other types of platforms. Ice camps can give good access to terrestrial mammals and breeding birds for direct observations, tagging, and collection of biopsy materials.
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From page 37... ...
bFor sea ice and climate studies, satellites, aircraft, and drifting buoys are important research platforms, and a research icebreaker is useful to collect ground-truthing data. For physical oceanographic needs, several different types of platforms are needed, to collect data at several scales.
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From page 38... ...
Ice camps provide opportunities for longer time-series measurements and for ocean-atmosphere-ice process studies that must be conducted over a full annual cycle. For climate studies, a research icebreaker is a lower priority.
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