Internal waves measurements with a ship‐mounted, 300‐kHz acoustic Doppler current profiler

1990 ◽  
Vol 87 (S1) ◽  
pp. S26-S26
Author(s):  
C. L. Trump ◽  
G. O. Marmorino
Keyword(s):  
Internal Waves ◽  
Acoustic Doppler Current Profiler ◽  
Current Profiler

scholarly journals Generation of Internal Waves by Eddies Impinging on the Western Boundary of the North Atlantic

2016 ◽  
Vol 46 (4) ◽  
pp. 1067-1079 ◽  
Author(s):  
L. Clément ◽  
E. Frajka-Williams ◽  
K. L. Sheen ◽  
J. A. Brearley ◽  
A. C. Naveira Garabato
Keyword(s):  
Internal Waves ◽  
North Atlantic ◽  
High Frequency ◽  
Large Scale ◽  
Acoustic Doppler Current Profiler ◽  
Relative Vorticity ◽  
Western Boundary ◽  
The North ◽  
Current Profiler ◽  
The North Atlantic

AbstractDespite the major role played by mesoscale eddies in redistributing the energy of the large-scale circulation, our understanding of their dissipation is still incomplete. This study investigates the generation of internal waves by decaying eddies in the North Atlantic western boundary. The eddy presence and decay are measured from the altimetric surface relative vorticity associated with an array of full-depth current meters extending ~100 km offshore at 26.5°N. In addition, internal waves are analyzed over a topographic rise from 2-yr high-frequency measurements of an acoustic Doppler current profiler (ADCP), which is located 13 km offshore in 600-m deep water. Despite an apparent polarity independence of the eddy decay observed from altimetric data, the flow in the deepest 100 m is enhanced for anticyclones (25.2 cm s−1) compared with cyclones (−4.7 cm s−1). Accordingly, the internal wave field is sensitive to this polarity-dependent deep velocity. This is apparent from the eddy-modulated enhanced dissipation rate, which is obtained from a finescale parameterization and exceeds 10−9 W kg−1 for near-bottom flows greater than 8 cm s−1. The present study underlines the importance of oceanic western boundaries for removing the energy of low-mode westward-propagating eddies to higher-mode internal waves.

scholarly journals A Modified Beam-to-Earth Transformation to Measure Short-Wavelength Internal Waves with an Acoustic Doppler Current Profiler

2005 ◽  
Vol 22 (5) ◽  
pp. 583-591 ◽  
Author(s):  
A. Scotti ◽  
B. Butman ◽  
R. C. Beardsley ◽  
P. Soupy Alexander ◽  
S. Anderson
Keyword(s):  
Internal Waves ◽  
Short Wavelength ◽  
Acoustic Doppler Current Profiler ◽  
Propagation Direction ◽  
Horizontal Distance ◽  
Massachusetts Bay ◽  
Backscatter Intensity ◽  
Current Profiler ◽  
Adcp Observations ◽  
Made In

Abstract The algorithm used to transform velocity signals from beam coordinates to earth coordinates in an acoustic Doppler current profiler (ADCP) relies on the assumption that the currents are uniform over the horizontal distance separating the beams. This condition may be violated by (nonlinear) internal waves, which can have wavelengths as small as 100–200 m. In this case, the standard algorithm combines velocities measured at different phases of a wave and produces horizontal velocities that increasingly differ from true velocities with distance from the ADCP. Observations made in Massachusetts Bay show that currents measured with a bottom-mounted upward-looking ADCP during periods when short-wavelength internal waves are present differ significantly from currents measured by point current meters, except very close to the instrument. These periods are flagged with high error velocities by the standard ADCP algorithm. In this paper measurements from the four spatially diverging beams and the backscatter intensity signal are used to calculate the propagation direction and celerity of the internal waves. Once this information is known, a modified beam-to-earth transformation that combines appropriately lagged beam measurements can be used to obtain current estimates in earth coordinates that compare well with pointwise measurements.

Klamath River Water Quality and Acoustic Doppler Current Profiler Data from Link River Dam to Keno Dam, 2007

2008 ◽  
Author(s):  
Annett B. Sullivan ◽  
Michael L. Deas ◽  
Jessica Asbill ◽  
Julie D. Kirshtein ◽  
Kenna D. Butler ◽  
...  
Keyword(s):  
Water Quality ◽  
River Water ◽  
Acoustic Doppler Current Profiler ◽  
River Water Quality ◽  
Klamath River ◽  
Current Profiler ◽  
Profiler Data
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