AND OUTFLOWS OF THE CHUKCHI SEA
(UW), Knut Aagaard (UW), Tom
With thanks to the US Coast Guard for ship support
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|CHUKCHI SEA BASICS
Chukchi Sea Basic Facts
- WHY is the Chukchi Sea important?
- WHAT are we doing?
SBI (Shelf Basin Interaction) program overview
The Pacific Influence on the Arctic Ocean's Lower Halocline
Woodgate et al., GRL, 2005
A Year in the Physical Oceanography of the Chukchi Sea: Moored Measurements from Autumn 1990 - 1991 Woodgate, et al, DSR, 2005
Circulation on the north central Chukchi Shelf. Weingartner et al., DSR, 2005
(see also JOSS/EOL site)
Healy Sept 2004 HLY-04-04
Healy Sept/Oct 2003 HLY-03-03
- also HLY-03-03 cruise website
Polar Star Jul/Aug 2002 AWS02
Alpha Helix 2004 (Aug/Sept)
Alpha Helix 2003 (July)
Alpha Helix 2002 (June)
GOTO DATA ARCHIVE
|CHUKCHI SEA BASICS
The Chukchi Sea, ~ 500 km wide (east-west), ~ 800 km long (north-south), is a shallow (~ 50 m deep) shelf sea just north of the Bering Strait and south of the Arctic Ocean proper. It is fed from the south by the Pacific water throughflow through the Bering Strait. Patterns of ice melt suggest the mean flow (which is northwards in the annual mean) is split into four main outflows - one through Barrow Canyon in the east, one through the Central Gap in the Central Chukchi Sea, one through Herald Canyon, just east of Wrangel Island, and one through Long Strait, between Wrangle Island and the mainland of Russia. There is also a seasonal current, the Siberian Coastal Current, present some years, flowing south through the Long Strait. For a full description of the flow structure see "A year in the Physical Oceanography of the Chukchi Sea".
The Chukchi Sea, being fed by nutrient-rich waters from the south, is one of the most abundant marine ecosystems in the world, including whales and walrus,
Waters from the Chukchi are an important source of nutrients, heat and freshwater for the Arctic Ocean. The nutrients support Arctic ecosystems. The heat can influence the ice. The freshwater can stratify the Arctic Ocean, and protect the ice from the warmer Atlantic waters below. Thus, the pathways of Pacific waters in the Arctic may affect the Arctic system.
Globally, the freshwater throughflow is an important part of global water cycles.
1990 and 1991, an extensive mooring project took place in the Chukchi
Sea, in conjunction with joint US and Russian Cruises. Year-round
moorings measured water velocity, temperature and salinity on 3 major
sections - one across the Bering Strait, one across the central Chukchi
and one across the major outflows of the Chukchi in the Arctic (i.e.
Barrow Canyon, the Central Channel, Herald Valley and Long Strait).
The data showed the Chukchi Sea to be strongly driven by the wind, but suggest that other than a cooling, there is little net change in salinity of waters as they pass through the Chukchi Sea. For more details, see "A Year in the Physical Oceanography of the Chukchi Sea".
The SBI (Shelf Basin Interaction) Program, sponsored by NSF and ONR is a multidisciplinary program to study physical, biological and chemical processes over the Chukchi Shelf, with a view to elucidate key shelf-slope-basin processes, which are relevant to local and Arctic climate.
The initial phase of the program consisted on the analysis of historic data. Phase II of the program was the field phase from 2002 to 2004, with up to 3 ice-breaker cruises a year, to study processes in spring, summer and autumn. Phase II also supported year-round moorings. One mooring project (Weingartner, Aagaard, Woodgate) focused on the outflows from the Chukchi Sea, measuring in Barrow Canyon, the Central Channel and (since Herald Valley is in Russian waters and no EEZ permission was available) at two sites on the northern Chukchi Slope. The second mooring project (Pickart) deployed a high resolution section of moorings on the Beaufort slope east of Barrow, to study the dynamics (especially eddy formation) of the Pacific waters flowing eastward along the northern coast of Alaska.
For more details see, SBI Healy 2003 Mooring Cruise.
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