Echo grid integration: A novel method for preprocessing multibeam water column data to quantify underwater gas bubble emissions

Water column imaging multibeam echo sounder systems (MBESs) are a promising technology for quantitative estimates of the gas bubble volume flow within large seepage areas. Considerable progress has been made in recent years toward applicable calibration methods MBESs as well developing inversion models to convert acoustically measured backscattering cross sections flow. However, still not commonly used assessments. A reason this is absence published processing that demonstrate how MBES data can be processed quantitatively represent streams. Here, we present novel method (echo grid integration) allows assessing aggregated section targets horizontal water layers. This derived value enables quantifying stream rates using existing acoustic methods. The presented based on averaging geo-referenced coefficients onto high-resolution 3D voxel-grid. results multiplied with voxel measurements total cross-section each cell. Individual gridded values cannot trusted because beam pattern effects cause individual “smear” over multiple grid-cells. true thus estimated integral grid-cells affected by smearing. Numerical simulation acquisition known assesses method's validity and quantify it's uncertainty different, realistic scenarios. found low measurement bias (< 1%), dispersion 5%) application quantification