Brett Hoyt, October 24, 2006


NOAA Teacher at Sea
Brett Hoyt
Onboard NOAA Ship Ronald H. Brown
October 8 – 28, 2006

Mission: Recovery and maintenance of buoy moorings
Geographical Area: Southeast Pacific, off the coast of Chile
Date: October 24, 2006

Data from Bridge 

Visibility:  12nm (nautical miles)
Wind direction:  140º
Wind speed:  4 knots
Sea wave height: 0-1ft
Swell wave height: 6-8 ft
Sea level pressure:  1018.5 millibars
Sea temperature:  18.1ºC or 64 ºF
Air temperature:  18.7ºC or 65 ºF
Cloud type: stratus

Deployment of the new tsunami buoy began at 6am on October 23.  The scientists deployed the buoy first and then plan to deploy the Bottom Pressure Recorder (BPR).  The reason for this is that the BPR must be located close enough to the buoy for the acoustic communication from the BPR to reach the surface buoy.  As there are only a few instruments from the Woods Hole Oceanographic Institution on the buoy, this deployment process only took a few hours instead of most of the day.  They plan on letting the buoy settle for many hours before they deploy the BPR.  One of the challenges for the tsunami buoy is that unlike the Stratus 7 buoy which had a “watch circle” (the distance the buoy could wander) of over 3 miles, the tsunami buoy has a watch circle of no more than 1,500 meters.  This difference is that you don’t want the buoy wandering out of range of the Bottom Pressure Recorder transmitter.  To achieve this, the scientists must make the mooring line exactly the right length.  The day before they deployed the buoy the scientists measured the contours of the ocean floor and knew precisely how deep the water was. At the last minute, the scientists from the Chilean Navy cut and spliced a piece of mooring line to exactly the right length.  (See photo)

The Scientists 

Here a scientist from the Chilean Navy is seen splicing in an eye into the line after it was cut to length.  This process ensures that the buoy stays in the right location and does not wander too far.

Here a scientist from the Chilean Navy is seen splicing in an eye into the line after it was cut to length. This process ensures that the buoy stays in the right location and does not wander too far.

The Machine 

The Chilean Government's tsunami buoy on station in the South Pacific.  This is only one half of the warning equation.

The Chilean Government’s tsunami buoy in the South Pacific. This is only half of the warning equation.

The Bottom Pressure Recorder (BPR) with its anchor attached.

The Bottom Pressure Recorder (BPR) with its anchor attached.

The Experiment 

There was no experiment.

Classroom Activities 

There is no classroom activity, as creating your own tsunami in the classroom would be way too messy.

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