Side scan sonar and swath bathymetry collected along OFOBS profiles during POLARSTERN cruise PS118

• Main Authors: Hehemann, Laura, Dreutter, Simon, Purser, Autun, Dorschel, Boris, Nordhausen, Axel
• Format: Other/Unknown Material
• Language: English
• Published: PANGAEA 2021
• Subjects: Antarctic Peninsula; Powell basin; Weddell Sea; Antarc*; Antarctic
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.930222; https://doi.org/10.1594/PANGAEA.930222

The Ocean Floor Observation and Bathymetry System (OFOBS), used during Polarstern research cruise PS118 to the Wedell Sea and Powell Basin, was a towed underwater camera system equipped with both a high-resolution photo-camera (iSiTEC, CANON EOS 5D Mark III) and a high-definition video-camera (iSiTEC, Sony FCB-H11). The cameras were mounted on a steel frame (150L x 92W x 105H cm), together with two strobe lights (iSiTEC UW-Blitz 250, TTL driven), three parallel laser pointers spaced with a distance of 50 cm used to estimate the size of seafloor structures, four LED lights, and a USBL positioning system (Posidonia) to track the position of the OFOBS during deployments. For PS101 the OFOS was upgraded with a 85 cm tail to additionally mount an EdgeTech 2205 bathymetric side scan and BlueView M900-130 forward looking sonar systems, to become the Ocean Floor Observation and Bathymetry System (OFOBS). Auxiliary sensors include an iXBlue PHINS 6000, and an AML Micro-X 6000 SV-Xchange sound velocity probe. An iXBlue DVL system was installed to augment the output of the PHINS 6000, but was not stable during PS118. The side scan sonar operated on two frequencies (230 kHz & 540 kHz) and the bathymetric array receives the high frequency. During PS118 the OFOBS has been flying on an average altitude of 3m above the seabed. The resulting achievable sonar ranges were 100m (low frequency) and 50m (high frequency) to both sides of the vehicle. Bathymetry in *_binned files is binned with 800 equidistant data points of 10cm distance, 40m to both sides. Additional _stave files contain the raw stave data. Stave files can be replayed with EdgeTech Discover Bathymetric to bin the bathymetry with different settings.