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Estimating Geostrophic Shear from Seismic Images of Oceanic Structure

Sheen, Katy L.; White, Nicky; Caulfield, Colm P.; Hobbs, Richard W.

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Authors

Katy L. Sheen

Nicky White

Colm P. Caulfield

Richard W. Hobbs



Abstract

It is shown that geostrophic vertical shear estimates can be recovered from seismic (i.e., acoustic) images of thermohaline structure. In the Southern Ocean, the Antarctic Circumpolar Current forms a loop within the Falkland Trough before it flows northward into the Argentine Basin. Seismic profiles that cross this loop show the detailed structure of different water masses with a horizontal resolution of O(10 m). Coherent seismic reflections are tilted in response to current flow around the Falkland Trough. Average slopes were measured on length scales that are large enough to ensure that the geostrophic approximation is valid (i.e., with a Rossby number <0.1). By combining shear estimates with satellite altimetric measurements and acoustic Doppler current profiles, geostrophic velocities can be calculated throughout the data volume. This technique for estimating geostrophic vertical shear from legacy seismic images yields useful information about the spatial and temporal variation of mesoscale circulation.

Citation

Sheen, K. L., White, N., Caulfield, C. P., & Hobbs, R. W. (2011). Estimating Geostrophic Shear from Seismic Images of Oceanic Structure. Journal of Atmospheric and Oceanic Technology, 28(9), 1149-1154. https://doi.org/10.1175/jtech-d-10-05012.1

Journal Article Type Article
Online Publication Date Sep 1, 2011
Publication Date Sep 1, 2011
Deposit Date Jan 16, 2012
Publicly Available Date Mar 28, 2024
Journal Journal of Atmospheric and Oceanic Technology
Print ISSN 0739-0572
Electronic ISSN 1520-0426
Publisher American Meteorological Society
Peer Reviewed Peer Reviewed
Volume 28
Issue 9
Pages 1149-1154
DOI https://doi.org/10.1175/jtech-d-10-05012.1

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Published Journal Article (1.6 Mb)
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Copyright Statement
© 2011 American Meteorological Society




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