AIDJEX Bulletin #40 - Polar Science Center - University of Washington

Since the addition of oceanographic sensors to these buoys was a significant
new step in the development of arctic data buoys, the program was
considered to be experimental, with the performance of the hardware a major
part of the results.
BUOY DESIGN
The buoy hull is a polyethylene tube 6 p11 long and 0.3 E in diameter
which is frozen into a hole drilled through the ice. The bottom of the tube
is plugged and has a fitting for the attachment of the upper current meter
from which the mast and lower current meter are suspended. The mast is composed
of ten sections of steel tubing, each about 3.3 m long and 2.5 cm in
diameter, which are joined with a tapered pin to insure the proper orientation
of the mast with respect to the buoy hull. This rigid suspension permits the
use of a single magnetic compass in the buoy hull to sense the azimuth of the
hull/mast assembly. The design, unfortunately, also permits 180" misalignment
of the current meters themselves with respect to the mast and hull. From a
ccmparison of the ice motion with the 2 m and 30 m currents, we believe that
the 30 m sensor of M/O 1 and both sensors of M/O 4 were installed backwards,
so that 180" were added to those bearings.
The electrical cable which carries the current meter data is routed up
the exterior of the buoy hull and enters through the top of the tube, eliminatir,g
the need for an underwater connector and making the substitution of
another current meter string feasible. The top of the tube is covered by a
larger diameter polyethylene "top hat" about 1 m tall which encloses the radio
antenna and to which a shielded air temperature sensor is attached. Inside
the buoy a vertical aluminum rack contains the radio transmitter, control
electronics, pressure sensor, compass, and carbon-air cell batteries sufficient
for one year of operation. This load, together with the weight of the
current meters, mast, and top hat, causes the buoy to float vertically with
about 0.5 m of the hull above the top of the ice. The rack is keyed to the
buoy hull to preserve the alignment of the compass and the oceanographic mast.
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