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Abstract Barrow Canyon 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 for more than 20 years, questions remain regarding the 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 outflow. During the summer survey, high percentages of Pacific water (summer water + winter water) were present 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 canyon proper and outer Chukchi shelf during the late‐fall survey, at 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. A cyclone‐like circulation was present in the canyon during both surveys, which was also evident in the satellite‐derived sea surface height anomaly field. We argue that this feature corresponds to an arrested topographic Rossby wave, generated as the outflow responds to the deepening bathymetry of the canyon. By applying a self‐organizing map analysis using the satellite altimeter data from 2001 to 2020, we demonstrate that such a cyclone‐like structure is a prevailing aspect of the canyon outflow.
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Evaluation of Shipboard and Satellite‐Derived Bathymetry and Gravity Data Over Seamounts in the Northwest Pacific Ocean
Abstract Earth's surface topography/bathymetry and gravity fields provide important constraints on crustal structure and the tectonic processes that act on it due, for example, to plate flexure and mantle convection. Such studies require, however, high accuracy measurements at a wide range of spatial scales. During the past few decades much progress has been made in the acquisition of bathymetry and gravity data using both shipboard and satellite altimeter methods. Surprisingly, there have been few comparisons of these data. During April–June, 2019 we had the opportunity onboard a R/VMarcus G. Langsethcruise in the northwest Pacific Ocean to compare data acquired with an EM122 Kongsberg swath bathymetry system and a refurbished Bell Aerospace BGM‐3 gravimeter with the most recent global bathymetry and gravity fields. We find that while the recovery of bathymetry and gravity from satellite radar altimeter data in areas of sparse shipboard data has been impressive, root mean square discrepancies in the range 175.5–303.4 m and 2.6–6.3 mGal exist between shipboard and satellite‐derived data. While these discrepancies are small, they are highly correlated and therefore have implications for the density structure, rock type and geological processes occurring on the deep seafloor. Shipboard data should continue to be acquired, especially over features such as seamounts, banks, and ridges that are associated with short wavelength (<25 km wavelength) bathymetric and gravimetric features beyond that is recoverable in satellite‐derived data.
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- PAR ID:
- 10453954
- Publisher / Repository:
- DOI PREFIX: 10.1029
- Date Published:
- Journal Name:
- Journal of Geophysical Research: Solid Earth
- Volume:
- 125
- Issue:
- 10
- ISSN:
- 2169-9313
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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