the ocean features monitored by the mooring include the cold halocline,
a layer within about 150 meters (500 feet) of the surface that's
as cold as minus 2°C, and the layer found generally at 200
to 400 meters (700 to 1,300 feet) depth that is 3° to 5°
warmer. The presence of the low-salinity, upper halocline is a
key to ice formation, since it acts as an insulating lid, keeping
the much-warmer underlying layer away from the ice. Scientists
are interested in detecting changes that might mean the water
in these layers is changing or mixing, something that could greatly
affect ice formation.
Retrieving and re-deploying the
team led by Dr.
Knut Aagaard of the Polar
Science Center at the University of Washington successfully
recovered the 4,300 meters (2.7 miles) long deep ocean mooring
near the North Pole, at 89° 33' N and 66° 40' E, and replaced
it with another. In turn, the new mooring will be replaced with
another next year for a total of three years of data. Recovering
a deep ocean mooring from beneath the ice is a complex
and difficult task . The only previous such mooring at the North
Pole was in place for only one month in 1979.
Unlike the observatory's drifting buoys that routinely broadcast
information to researchers via satellite, the top of the mooring
is beneath the ice and each instrument must record internally
and be retrieved to recover any of the data. The scientists were
relieved to find the instruments on the first mooring recording
and in good condition. Instruments on each mooring include seven
conductivity-temperature recorders to measure the warming, cooling
and salinity changes in different layers of the ocean; four current
meters to measure speed and direction of flow; an acoustic doppler
current profiler to provide detailed information on the vertical
structure of the ocean currents, as well as the ice drift; and
an upward-looking sonar to measure ice thickness. Among other
measurements, the instruments monitor the condition of the upper
400 meters (1,300 feet) of the ocean.
2002 is third year for drifting
Unlike the mooring, the drifting buoys transmit their data to
a satellite, so one need not recover the buoy to get the data,
which is constantly accessible. However, the buoys are vulnerable
to damage from ice activity like pressure ridging and lead shearing
or polar bears. As the Arctic ice continues its thinning trend,
it has become more challenging to pick a good floe on which a
buoy may survive the year and ultimately drift out Fram Strait
into the greenland Sea. Instruments on the buoys measure and report
information about weather conditions and the amount of heat reaching
the ice from the sun and atmosphere, plus ice thickness and the
state of the upper ocean. This year a substantial floe 2.5 meters
thick was found for the buoy array, about a kilometer out from
the camp at Borneo. Everything for the buoys had to be dragged
out from camp on akias or banana sleds.
Physical oceanographer Dr. Takashi Kikuchi and marine technician
Marine Science and Technology Center deployed their fourth
Compact Arctic Drifter (JCAD-4). It measures ocean
temperature, salinity and currents, atmospheric temperature and
pressure, and wind velocity. The use of a J-CAD each year
of the North Pole Environmental Observatory amounts to a $2.5
million contribution (over five years) of equipment from Japan.
Also being installed will be five buoys from NOAA's Pacific
Marine Environmental Laboratory of Seattle and the U.S.
Army's Cold Regions Research and Engineering Laboratory
of Hanover, N.H. A meteorological buoy will measure wind speed,
atmospheric pressure and temperature. Two radiometer buoys will
measure short-wave radiation from the sun and long-wave radiation
from the atmosphere. Two ice-mass balance buoys measure ice temperature
profiles and snow thickness. As an entertaining sidelight, one
PMEL buoy was equipped with a North
Pole WebCam, allowing us to observe conditions at the
welcomes the Autonomous
Ocean Flux Buoy, capable of measuring ocean heat and salinity
as it moves from the warmer interior of the ocean up and through
the ice. This "flux" is influenced by mixing in the
upper layers of the ocean, which the buoy will also monitor. This
buoy has been developed by Dr.
Tim Stanton's Ocean Turbulence Laboratory at the Naval
Postgraduate School in Monterey, California, under National
Science Foundation Grant OPP 0084858.
surveying includes fine-scale survey of Lomonosov Ridge
Using an extremely lightweight winch and a helicopter instead
of an airplane made it possible for Dr.
James Morison of the Polar
Science Center at the University of Washington to land
at 8 locations across 100 miles of ice for the most-detailed survey
ever of the water properties over the Lomonosov Ridge. Only 1,000
meters below the surface in places, the Lomonosov is the Arctic
Ocean's shallowest major ridge. Two branches of warmer waters
from the Atlantic seem to travel along the ridge before exiting
the Arctic along the east coast of Greenland. Whether they mix
or remain separate are among the unknowns. It also appears that
the ridge is one of the places where these warmer waters spread
to deeper basins. At each location, the helicopter was able to
land adjacent to very thin ice and lower an instrument profiling
temperature, salinity and dissolved oxygen down to 500 meters.
previous years, hydrographic stations will be taken from a Twin
Otter skiplane across a much wider area. These will included drawing
water samples to measure concentrations of such chemical tracers
as O2 isotopes, barium, and nutrients out in the Makarov Basin.