Thursday, October 3, 2013

The WHOI Buoy

Guest Blogger:  Jeff Lord (WHOI)

The WHOI buoy is populated with high-resolution meteorological instruments and over 60 instruments along the mooring line between the surface and 2000 m depth.  

Meteorological instruments include wind speed and direction, barometric pressure, humidity, air temperature, precipitation and solar radiation. This data is transmitted back to WHOI via satellite in near-real time. Subsurface instruments record ocean currents, temperature, and salinity at different depths. The data from subsurface instruments is collected after recovery.

The surface buoy is a 9-foot diameter foam hull, with an instrument well in the center. The instrument well holds data loggers, transmitters, and 5760 D-cell batteries to power the electronics on the buoy.

The water depth at the buoy site is 5240 meters (3.25 miles). The mooring construction is a combination of wire rope, chain, and synthetic line.  Instruments are either clamped to wire, or mounted on titanium load bars inserted into the mooring with shackles between segments of chain or wire rope.

A 10,000-pound anchor holds the mooring in place.

Just above the anchor is an acoustic release that allows the mooring to be decoupled from the anchor for recovery. Above the acoustic release are 80-17” glass spheres in plastic housings that act as backup floatation.

If the mooring line failed at any point below the buoy, the rest of the mooring can be recovered from the sea floor by releasing the anchor. The backup floatation will bring the remaining mooring line and instruments to the surface for recovery.

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