The encoding of wind forcing into the Pacific-Arctic pressure head, Chukchi Sea ice retreat and late-summer Barrow Canyon water masses

摘要

Barrow Canyon, which incises the northeast corner of the Chukchi Sea shelf, is a major conduit through which Pacific-origin waters carrying nutrients, biota, freshwater, and heat enter the Arctic Ocean. As such, Barrow Canyon was adopted as a long-term monitoring site for the Distributed Biological Observatory (DBO) in 2010. However, annual hydrographic surveys across Barrow Canyon, conducted during late August 2005-2015 along a location near what is the Barrow Canyon DBO survey line and in support of other research programs, extend and complement the DBO hydrographic record. These complementary hydrographic surveys show that volumes of Pacific-origin and melt water masses in Barrow Canyon are significantly-correlated with daily sea ice areas in the eastern Chukchi Sea for most of the May-August ice retreat season. Year-to-year differences in the timing and pattern of sea ice retreat across the Chukchi Sea are also shown to be well-correlated with changes in seasonally averaged regional winds particularly as defined by the strength and longitudinal location of the Beaufort Sea High pressure cell. These interdependent wind-ice retreat-water mass relationships are largely predicated on wind stress curl-driven changes to sea level in the East Siberian Sea/northwestern Chukchi Sea. Statistically significant correlations among wind-forced sea surface heights, ice areas, and water mass volumes suggest that, during the ice retreat season, the East Siberian Sea/western Chukchi Sea region serves as the Arctic terminus for the Pacific-Arctic pressure head.