Page 44: of Marine Technology Magazine (March 2018)

ADCPs See Action in OOI’s Cabled Observatory

Sustained and Interactive Monitoring of NE Pacif c Ocean

By Peter Spain Ph.D., Teledyne RD Instruments

ADCPs are sonar systems that mea- pler Effect. It tells how fast the current is rine scientists and engineers, high-tech sure motion underwater. Using sound moving and in what direction. ocean observatories are now opera- waves, they work like hand-held radars Sound waves propagate through the tional. These sites provide a continuous used by police to catch speeding motor- water column so echoes are returned and presence in the ocean for sustained and ists. To measure motion, ADCPs emit processed from many depths. The verti- interactive observing. Many combine sound bursts along beams angled down- cal range of this collection of measure- innovative infrastructure with multi-dis- ward. ments - called a pro? le of ocean current cipline marine sensors.

Echoes are returned due to scattering velocities - is greater for lower frequen- Installed at various depths, these ob- off particles. Because zooplankton and cy sound waves. servatories exist worldwide in diverse suspended sediments are carried by the marine environments. Their purpose is moving water, echoes scattered off them to measure the oceanic and seabed en-Introduction carry a change in pitch; this is the Dop- Thanks to a spirited cadre of ma- vironments in strategic locations for ex-

Fig.1. En route to sites off the Oregon coast, sev- eral ADCPs can be seen installed in the ? xed plat- form of Shallow Pro? ler

Moorings.

Credit: M. Elend, University of Washington, VISIONS ‘16 expedition.

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