Statistics of internal tide bores and internal solitary waves observed on the inner continental shelf off Point Sal, California

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Author
Colosi, John A.
Kumar, Nirnimesh
Suanda, Sutara H.
Freismuth, Tucker M.
MacMahan, Jamie H.
Date
2018-01Metadata
Show full item recordAbstract
Moored observations of temperature and current were collected on the inner continental shelf off Point Sal,
California, between 9 June and 8 August 2015. The measurements consist of 10 moorings in total: 4 moorings
each on the 50- and 30-m isobaths covering a 10-km along-shelf distance and an across-shelf section of
moorings on the 50-, 40-, 30-, and 20-m isobaths covering a 5-km distance. Energetic, highly variable, and
strongly dissipating transient wave events termed internal tide bores and internal solitary waves (ISWs)
dominate the records. Simple models of the bore and ISW space–time behavior are implemented as a temperature
match filter to detect events and estimate wave packet parameters as a function of time and mooring
position. Wave-derived quantities include 1) group speed and direction; 2) time of arrival, time duration,
vertical displacement amplitude, and waves per day; and 3) energy density, energy flux, and propagation loss.
In total, over 1000 bore events and over 9000 ISW events were detected providing well-sampled statistical
distributions. Statistics of the waves are rather insensitive to position along shelf but change markedly in the
across-shelf direction. Two compelling results are 1) that the probability density functions for bore and ISW
energy flux are nearly exponential, suggesting the importance of interference and 2) that wave propagation loss
is proportional to energy flux, thus giving an exponential decay of energy flux toward shore with an e-folding
scale of 2–2.4 km and average dissipation rates for bores and ISWs of 144 and ¯ ¹, respectively.
Description
Manuscript received 6 March 2017, in final form 31 July 2017
The article of record as published may be located at http://journals.ametsoc.org/doi/full/10.1175/JPO-D-17-0045.1
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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.Collections
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