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Abstract Data from two moorings deployed at 166°W on the northern Chukchi shelf and slope from summer 2002 to fall 2004, as part of the Western Arctic Shelf‐Basin Interactions program, are analyzed to investigate the characteristics and variability of the flow in this region. The depth‐mean velocity at the outer‐shelf mooring is northeastward and bottom‐intensified, while that at the upper‐slope mooring is northwestward and surface‐intensified. This, together with results from a high resolution ocean and sea ice reanalysis, indicates that the outer‐shelf mooring sampled the seaward edge of the Chukchi Shelfbreak Jet, while the upper‐slope mooring sampled the shoreward edge of the Chukchi Slope Current. The coupled variability in velocity at both sites is related to the wind stress curl over the Chukchi Sea shelf, likely via Ekman dynamics and geostrophic set up, analogous to the dynamics of both currents closer to Barrow Canyon near 157°W. Hydrographic signals are analyzed to elucidate the origin of the water masses present at this location. It is argued that the annual appearance of Pacific‐origin warm water at the outer‐shelf (upper‐slope) mooring in late‐fall and winter originates from Herald (Barrow) Canyon some months earlier. Our results constitute the first robust evidence that the westward‐flowing Chukchi Slope Current persists this far west of Barrow Canyon.
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This content will become publicly available on November 8, 2025
Nutrient‐Rich Winter Water Formation on the Beaufort Shelf, Arctic Ocean
Abstract Newly ventilated winter water (NVWW) is a cold, salty, nutrient‐rich water mass that is critical for supporting the ecosystem of the western Arctic Ocean and for ventilating the halocline in the Canada Basin. While the formation of NVWW is well‐documented on the Chukchi shelf, there remain fundamental questions regarding its formation on the western Beaufort shelf. In this study, we use hydrographic data from two late‐fall cruises in 2018 and 2022 to investigate the roles of sea ice production and wind‐driven upwelling in the formation of NVWW and the implications for the nutrient content of the water. For each of the shipboard transects, we apply proxies for the extent of the winter water formation and the strength of the associated upwelling, respectively. It is demonstrated that the NVWW attains higher levels of nitrate due to two factors: (a) more active formation of the water associated with enhanced sea ice production and (b) more extensive upwelling of water high in nutrients from the basin to the shelf following an easterly wind event. The latter process would be less common on the wide Chukchi shelf. These findings have significant implications for the regional primary production.
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- Award ID(s):
- 2135537
- PAR ID:
- 10579581
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Oceans
- Volume:
- 129
- Issue:
- 11
- ISSN:
- 2169-9275
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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