Satellite and Oceanographic Observations of the Warm Coastal Current in the Chukchi Sea

Abstract

Selected infrared images obtained by the NOAA satellites have increased our understanding of the formation and extent of the Alaskan Coastal Current, a movement of relatively warm water from the vicinity of Bering Strait northward along the Alaskan coast past Point Barrow and eventually into the Arctic Ocean where it disperses. Oceanographic measurements made from an icebreaker during the same period give spot checks on the depth of the warm layer, as well as the outline of a downward trend of the current when it is blocked by the ice. A study of satellite and oceanographic observations over a seven-year period, 1974-1980, reveals many interesting features of the flow and shows the annual variability. The northward flow and the shape of the ice edge are interrelated in that the flow is partially blocked by the ice and the ice is melted by the oncoming warm water. The solar-heated waters in Kotzebue Sound, Norton Sound, and along the coast to the south are seen as a major source of the heat in the coastal current.

The Large Scale Ocean Circulation and Physical Processes Controlling Pacific-Arctic Interactions

“…More than half of the heat fl ux through CL1 and CL2 is found in the coastal sections (55 % and 71 %, respectively). The relative increase of heat fl ux between ACC1 and ACC2 supports the fi nding of Ahlnäs and Garrison ( 1984 ) that the solar-heated waters in the Kotzebue Sound and along the coast are some of the main sources of heat in the Alaskan Coastal Current. However, as one moves farther north, little of the heat or volume fl ux across CL3 is found in the shorter coastal section ACC3.…”

“…Still, a more realistic representation of winds and local fresh water discharge from the Siberian and Alaskan coasts as well as higher spatial resolution would further improve model skill in simulating both of these coastal currents (Maslowski and Walczowski 2002 ;Newton et al 2008 ). It is important to note, that observations made by Paquette and Bourke ( 1974 ) and Ahlnäs and Garrison ( 1984 ) show that the ACC is enhanced by solar-heated waters in Kotzebue and Norton sounds and it impacts the local ice edge position downstream.…”

The Pacific Arctic Region

“…The main eastern branch is directed primarily northward to the east of Herald Shoal and west of the 25-m isobath. It is important to note, that observations made by Paquette and Bourke ( 1974 ) and Ahlnäs and Garrison ( 1984 ) show that the ACC is enhanced by solar-heated waters in Kotzebue and Norton sounds and it impacts the local ice edge position downstream. An offshoot of the western branch fl ows through Long Strait (between Wrangel Island and Siberia), most of which encircles the island in an anticyclonic fashion and eventually joins the Central Channel fl ow, however a small portion of the current continues along Siberia to the northwest near the coast.…”

The Barents and Chukchi Seas: Comparison of two Arctic shelf ecosystems

“…These waters are saltier and richer in nutrients than Alaskan Coastal Water (Springer et al, 1989). Topographic shoals in the northern Chukchi Sea split the northward flow of Bering Sea Water into 3 branches (Ahlnäs and Garrison, 1984; Paquette and Bourke, 1981;Weingartner et al, 2005;Woodgate et al, 2010). One branch flows east of Hanna shoal and continues to Barrow Canyon, one is west of Herald Shoal through Herald Canyon, and other is between the shoals via what is called the Central Channel ( Fig.…”