the Expedition ARKTIS-XIX/4 of the research vessel POLARSTERN ...

3 Bathymetry
S. Gauger, B. Reese, A. Winkler
During the expedition ARK-XIX/4 the bathymetry working group performed 58 days of
Hydrosweep DS2 (HYDROgraphic multibeam SWEEPing survey echosounder -
Deep Sea 2) measurement. The main characteristics of the multibeam sonar system
are the 90°/120° coverage angle in which the seafloor is depicted with 59 specific
values for water depths across the ship’s long axis. The accuracy of this
measurement is ~0.5% of the water depth. For the slant range correction of the sonar
beams the automatic self calibration process was used. The observed depths are
between several decadic meters in the coastal regions of Greenland and up to 5500
meters in the Molloy deep.
The survey was performed mainly during seismic measurements in the Greenland
Sea (72°N - 77°N and 0° - 25°W), which were carried out by the geophysical working
group. The seismic profiles along and across the East Greenland shelf edge led us to
the three fjords Ardencaple Fjord, Godthaab Golf and Kejser Franz Josephs Fjord.
Especially a bathymetric profile in the Ardencaple Fjord continued a measurement
from the Polarstern expedition ARK-X/1 in 1994. The profile took five hours of
measurement time with a coverage angle of 120°. The figure 3-1 shows the surveyed
area and gives a good overview of the rough fjord topography.
The collected data within the region 73°40’N to 75°10’N and 3°W to 15°W were taken
into account particularly. They will be used to extend the existing data base of the
ARKTIEF project. The data for this project have been collected while former
Polarstern expeditions to investigate the Ardencaple Channel System.
Additionally an important work during the cruise was the producing of cleaned
navigation files with the associated depth values in a five seconds interval for the
geophysical working group daily. These data will be used by the geophysicists to
process the gravity values measured by the ships gravimeter. The needed data
values were extracted from the PODAS database. Then they were edited using the
Caris HIPS software and given to the geophysical working group after reformatting to
the so called Nak-format.
Furthermore during the second part of the expedition the survey went on along the
oceanographic profile at 78°50’N in the Fram Strait between 8°E and 4°W.
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