SC2020_V01 EM2040C multibeam water column bubble experiments

Brief description

This record describes multibeam echo sounder data collected during field experiments on RV South Cape survey SC2020_V01. CSIRO’s Oceans & Atmosphere Shallow Survey Facility (SSF) undertook multibeam water column experiments over an artificial seep deployed near Kingston Beach, southern Tasmania. The goal of the experiments was to characterize the utility of high frequency multibeam water column data for the detection of gas seeps in very shallow water (<20 m). These experiments were aligned to inform the ANLEC R&D Carbon Capture and Storage Marine Monitoring and Verification (MM&V) project (ANLEC R&D 7-0816-0305) on the application of multibeam water column data for the detection of gas seeps in shallow water as a regular monitoring tool. The Geophysical Survey & Mapping team single-head EM2040C multibeam was mobilised on RV South Cape and bathymetry and water column data were collected over a custom-built bubble release system to simulate a shallow water gas seep at a test site near Kingston Beach, southern Tasmania. The EM2040 provides a 1.3° by 1.3° transmit and receive angular resolution respectively. Data were acquired at 300kHz frequency using single swath mode, short CW pulse, beam spacing set at equidistant and sector coverage set to 65° port and starboard (total coverage 130°). Data are stored in *.all raw format for bathymetry and backscatter and in *.wcd format for water column backscatter at the CSIRO. There are 397 *.all and 373 *.wcd files totaling 129 GB of raw multibeam data in this dataset. Sound velocity profiles were applied to the data during data acquisition. Bathymetry data contained in *.all format have been corrected for motion and position. Additional information regarding this dataset, including further information on processing streams, is contained in the GSM data acquisition and processing report (sc2020_v01_Bubble_experiments_CCS_Rev_1.pdf). Water column data were post-processed using custom MATLAB workflows. A variety of workflow methods were tested, with the processing results of each available in *.txt and *.jpg format. Additional data products may be available on request.