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Ocean Drifters Investigating Ocean Currents
What is a drifter buoy?
These are the parts
of a drifter buoy:
(images courtesy of the National Oceanographic
A drifter buoy is made up of three parts.
The sphere or floater (about 14 inches in diameter)
floats just below the ocean surface. It holds an antenna for sending
information to a satellite orbiting above the Earth.
The "holey sock" drogue is attached to it. The
drogue usually hangs down about 15 meters. It acts like an underwater
sail. When it is pushed by the ocean current, the drogue helps the
drifter move with the flow of water. Without a drogue, the buoy
would move because of wind and waves, not the current.
The sensors measure ocean conditions, such as the sea surface
water temperature. Sensors can also measure wind, ocean color, and
other things. The information (data) is measured continuously. Then,
an average of the measurements is calculated every hour. The data
must be sent to a satellite orbiting the Earth. When a satellite
passes overhead (about every six hours), the sets of data are sent
to the satellite. The location of the buoy is also sent to the satellite.
Then all this information is sent from the satellite to computers
at a ground station on land. Scientists read the information from
computers. Scientists use this information to learn about the ocean.
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