Arctic | Climate and Oceanography
New insights on the pathways of Pacific water across the Chukchi shelf based on the Distributed Biological Observatory repeat sections Presenter: Robert Pickart , rpickart@whoi.edu, Woods Hole Oceanographic Institute Peigen Lin , plinwhoi@gmail.com, Shanghai Jiao Tong University Pacific-origin water follows several pathways across the Chukchi shelf from Bering Strait to the deep interior basin, impacting the regional ecosystem in profound ways. Basic questions remain unanswered, however, regarding the division of volume transport between the branches, the evolution of water masses along the routes, and the variability of the flow on timescales of days to seasons. In this presentation we use an extensive collection of repeat hydrographic sections along two of the Distributed Biological Observatory (DBO) lines on the Chukchi shelf, plus repeat occupations of the Bering Strait line, to address some of these questions. Together with climatological shipboard velocity data, we can, for the first time, robustly distinguish between the Alaskan Coastal Current and the Central Channel branch as the two currents flow northward across the shelf. Our analysis focuses on time periods when wind-driven upwelling was not occurring, in order to quantify the background state. The properties of the water masses advected by the two branches, and their seasonality, are quantified. Following this, the nature of the mesoscale variability is investigated. Two dominant modes were revealed, one associated with the Alaskan Coastal Current and the other with the Central Channel branch. The underlying causes of the variability are addressed.
Alaska Marine Science Symposium 2023 121
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