Suspended particulate layers and internal waves over the southern Monterey Bay continental shelf: An important control on shelf mud belts?
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Authors
Cheriton, Olivia M.
McPhee-Shaw, Erika E.
Shaw, William J.
Stanton, Timothy P.
Bellingham, James G.
Storlazzi, Curt D.
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Date of Issue
2014
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Abstract
Physical and optical measurements taken over the mud belt on the southern continental
shelf of Monterey Bay, California documented the frequent occurrence of suspended
particulate matter features, the majority of which were detached from the seafloor, centered
9–33 m above the bed. In fall 2011, an automated profiling mooring and fixed
instrumentation, including a thermistor chain and upward-looking acoustic Doppler current
profiler, were deployed at 70 m depth for 5 weeks, and from 12 to 16 October a long-range
autonomous underwater vehicle performed across-shelf transects. Individual SPM events
were uncorrelated with local bed shear stress caused by surface waves and bottom currents.
Nearly half of all observed SPM layers occurred during 1 week of the study, 9–16 October
2011, and were advected past the fixed profiling mooring by the onshore phase of
semidiurnal internal tide bottom currents. At the start of the 9–16 October period, we
observed intense near-bed vertical velocities capable of lifting particulates into the middle
of the water column. This ‘‘updraft’’ event appears to have been associated with nonlinear
adjustment of high-amplitude internal tides over the mid and outer shelf. These findings
suggest that nonlinear internal tidal motions can erode material over the outer shelf and that,
once suspended, this SPM can then be transported shoreward to the middle and shallow
sections of the mud belt. This represents a fundamental broadening of our understanding of
how shelf mud belts may be built up and sustained.
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Article
Description
The article of record as published may be located at http://dx.doi.org/10.1002/2013JC009360
Series/Report No
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Oceanography
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Sponsors
This project was funded by the National Science Foundation (grant OCE0961810 to McPhee-Shaw, Bellingham, Shaw, and Stanton), and by the U.S. Geological Survey.
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Citation
Cheriton, O. M., E. E. McPhee-Shaw, W. J. Shaw, T. P. Stanton, J. G. Bellingham, and C. D. Storlazzi (2014), Suspended
particulate layers and internal waves over the southern Monterey Bay continental shelf: An important control on shelf mud belts ?,
J. Geophys. Res. Oceans, 119, 428–444, doi:10.1002/2013JC009360.
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This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.