Preface The expedition ARK XIX/3 with the German icebreaking RV ...

First results show that the seafloor of the channel is flat on the micro bathymetric scale,
i.e. no distinct features at the scale of some 10cm have been found in the preliminary
processed data. However, height changes of a few meters are visible within the grid
survey areas at the scale of >10m. The micro bathymetry data are clearly influenced by
the movement of "Victor 6000" (Fig. A4.2.2-3). Insufficient pitch compensation of the ROV
becomes particularly visible in the data set as a wave structure affecting the entire data
set.
Fig. A4.2-3: Micro bathymetry recorded by Seabat 8125 mounted on "Victor 6000". The grid has a
size of approximately 150m x 200m. The depth ranges between 1525m (blue) and 1520m (red).
The height of these waves was determined as approximately 6cm that is close to the
Seabat accuracy. Navigation errors are also seen in the overlapping areas of adjacent
track lines. Due to the low topographic variation of the seafloor at the channel bottom
these artifacts are very pronounced and dominate the data set. The wavelength of the
Hydrosweep acoustic pulse is approximately 10cm. Thus, surface topography of the size
of the artificial waves can affect the backscattering of the pulse. In order to perform
statistical analyses of the micro bathymetry, these errors first need to be removed from
the data. To realize this process, thorough data analyses of the motion sensors of "Victor
6000" and other related navigation parameters need to be conducted. So far angular
backscatter data of the Seabat System have not been processed.
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