Shot point coordinates of a parasound profile during METEOR cruise M76/3a ...

• Main Authors: Wenau, Stefan, Spieß, Volkhard, Keil, Hanno, Fei, Tai
• Format: Dataset
• Language: English
• Published: PANGAEA 2018
• Subjects: LATITUDE; LONGITUDE; Number; UTM Easting, Universal Transverse Mercator; UTM Northing, Universal Transverse Mercator; UTM Zone, Universal Transverse Mercator; Underway cruise track measurements; M76/3a; Meteor 1986; Center for Marine Environmental Sciences MARUM; Antarc*; Antarctic; North Atlantic Deep Water; North Atlantic
• Online Access: https://dx.doi.org/10.1594/pangaea.893340; https://doi.pangaea.de/10.1594/PANGAEA.893340

This study investigates the geometry and temporal variation of a prominent gas bubble stream from a seafloor pockmark in the Lower Congo Basin. We present results of a 3D gridding approach of singlebeam echosounder water column data (Parasound 18 kHz) that increases the lateral resolution and improves the localization of anomalies beyond the inherent depth-dependent footprint size of the sonar system. This allows a detailed reconstruction of gas bubble trajectories through the water column, revealing a stable gas bubble stream for the deepest 1000 m. The bubbles are shifted laterally by ∼200 m in the transition zone between North Atlantic Deep Water and Antarctic Intermediate Water with a reconstructed current velocity of ∼4 cm/s. The direction of lateral shift varies throughout the ∼15 h survey possibly because of internal waves and small-scale eddies at the water mass boundary. Furthermore, a stacking of SBES water column data acquired during sampling stations showed a periodic variation in seepage ... : Supplement to: Wenau, Stefan; Spieß, Volkhard; Keil, Hanno; Fei, Tai (2018): Localization and characterization of a gas bubble stream at a Congo deep water seep site using a 3D gridding approach on single-beam echosounder data. Marine and Petroleum Geology, 97, 612-623 ...