Tim Duda, John Toole, Jim Ledwell
Woods Hole Oceanographic Institution
Woods Hole MA 02543
BBTRE Shearmeter Results JPO manuscript
BBTRE Shearmeter Operations Technical Report WHOI-2002-01
Shearmeter home page
Shearmeter Brazil Basin Test Mission webpage
These shearmeters are the second design to be deployed in the ocean. This version 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 to allow air shipment to the RV Knorr, with three sections of equal length.
The goal of the mission is to collect long time series of shear and gradient Richardson number at the upper edge of the Antarctic Bottom Water, where the tracer dispersion study is being carried out, and in the water above.
One instument surfaced on schedule, 01 Nov. 2000. It floated at 3100 m depth rather than the intended 3500 m. It sank 100 meters over six months at a fixed rate. The compass failed to operate correctly, probably due to extraneous magnetic fields in the instrument, and the rotation counting sytem produced aliased signals which are probably not usable. Two sound sources were heard intermittently so the trajectory can be computed. The compass functions correctly in the damaged and returned instrument and the cause of the rotation problem has not been identified.
The shearmeters were built by Webb Research Corporation.
WHOI AOPE Dept.
Coastal and Ocean Fluid Dyn. Lab Webpage
Ocean Acoustics Lab Webpage (My formal affiliation.)
Webb Research Corp.Webpage