Guiana Abyssal Gyre Experiment Shearmeters

Tim Duda
Woods Hole Oceanographic Institution
Woods Hole MA 02543


Shearmeter home page

Seven shearmeters were deployed in February 2001.  Two shearmeters were launched at  13.5 N, 55W over smooth bathymetry, and five were launched at 13 N, 49 W over rough mountains southeast of the MAR crest.  Floats were ballasted to drift at 3000, 3500 and 4000 decibars; one at 3000 and one at 4000 at the western site, two at 3000, one at 3500 and two at 4000 at the rougher eastern site. The first figure below shows the two sites (red squares) and selected bathymetric contours.

These shearmeters will listen to 260-Hz acoustic sources, allowing their trajectories to be computed.  They are made of anodized and painted 7075  high-strength tubing.   They are sectional , with two sections of equal length.

The goal of the mission is to collect long time series of shear and gradient Richardson number in the abyssal currents and water masses (Antarctic Bottom Water and North Atlantic Deep Water).

I have the green shirt in the photos below. Scott Worrilow, Ryan Schrawder, Dr. Claudia Cenedese, Chief Scientist Richard Limeburner, and the RV Oceanus crew helped deploy the floats.

The shearmeters were built by Webb Research Corporation.




Coastal and Ocean Fluid Dyn. Lab Webpage
Ocean Acoustics Lab Webpage (My formal affiliation.)
Webb Research Corp.Webpage