Arctic | Climate and Oceanography
Structure and variability of Barrow Canyon outflow from two high-resolution shipboard surveys in 2018 Presenter: Jie Huang , jhuang@whoi.edu, Woods Hole Oceanographic Institution Robert Pickart , rpickart@whoi.edu, Woods Hole Oceanographic Institute
Nicholas Foukal , nfoukal@whoi.edu Michael Spall , mspall@whoi.edu Peigen Lin , plin@whoi.edu
Barrow Canyon, located in the northeast Chukchi Sea, is a critical choke point where Pacific-origin water, heat and nutrients enter the interior Arctic. While the flow through the canyon has been monitored since the early 2000s, questions remain as to the mechanisms and dynamics by which the Pacific-origin water is fluxed offshore, as well as what drives the variability. In 2018 two high-resolution shipboard surveys of the canyon were carried out – one in summer and one in fall – to investigate the water mass distribution and velocity structure of the canyon outflow. During the summer survey, high percentages of Pacific Water (combination of summer water and winter water) resided seaward of the canyon, associated with strong northward outflow from the canyon and a well-developed westward-flowing Chukchi Slope Current (CSC). By contrast, high percentages of Pacific Water were confined to the shelf and slope region during the late-fall survey, during which time the canyon outflow and CSC were considerably weaker. These differences can be attributed to differences in wind forcing during the time period of two surveys. Notably, a cyclone-like circulation was present in the canyon during both surveys. Such a structure is also found in satellite-derived sea surface height and surface geostrophic velocity fields. We argue that this feature corresponds to an arrested topography Rossby wave, generated as the outflow responds to the bathymetry of the canyon. By applying a self-organization map analysis using the satellite altimeter data from 1993 to 2020, we demonstrate that such a cyclone-like structure is prevalent in Barrow Canyon. Further analysis of the satellite data, in conjunction with historical hydrographic data, suggests that this structure can significantly impact the distribution and fate of Pacific Water emanating from the canyon.
Alaska Marine Science Symposium 2023 115
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