![]() ![]() ![]() Along with the sound speed profile, which is critical for ray-tracing, knowledge of the temperature and the salinity variability is crucial in the calculation of appropriate absorption coefficients for acoustic backscatter processing ( Masetti et al., 2017 Malik et al., 2018 Montereale-Gavazzi et al., 2019). Such refraction-induced depth biases can quickly cause the survey to exceed the allowable error tolerances prescribed by best practices and by international and national survey specifications ( UKHO, 2004 IHO, 2011 NOAA, 2019a). If the timing of sound speed casts does not properly capture the spatio-temporal variability of the ocean environment, the under-sampled water column produces refraction-induced depth biases in the collected soundings ( Beaudoin, 2010 Wilson et al., 2013 Lucieer et al., 2016). Nevertheless, the resulting products (e.g., bathymetric grids, acoustic backscatter mosaics) and the overall operational efficiency of surveys are often affected by the poor awareness of the oceanographic environment in which the surveys are conducted ( Lurton et al., 2015 Hughes Clarke et al., 2017 Mayer et al., 2018). Recent technological advances in seafloor mapping systems have greatly improved the quality and the efficiency of data acquisition ( Mayer, 2014 Hughes Clarke, 2018 Lamarche and Lurton, 2018). After having described the techniques adopted for each use case and their implementation as an extension of publicly available ocean mapping tools, this work provides evidence that the adoption of these techniques has the potential to improve efficiency in survey operations as well as the quality of the resulting ocean mapping products. The study explores two main use cases: the use of predicted oceanographic variability in the water column to enhance and extend (or even substitute) the data collected on-site by sound speed profilers during survey data acquisition and, the uncertainty estimation of oceanographic variability as a meaningful input to estimate the optimal time between sound speed casts. With the intention of rectifying this situation, this work evaluates some possible ocean mapping applications for commonly available oceanographic predictions by focusing on one of the available regional models: NOAA’s Gulf of Maine Operational Forecast System. Increasingly reliable ocean nowcast and forecast model predictions of key environmental variables – from local to global scales – are publicly available, but they are often not used by ocean mappers. 2NOAA, National Ocean Service, Coastal Marine Modeling Branch, Durham, NH, United Statesĭespite recent technological advances in seafloor mapping systems, the resulting products and the overall operational efficiency of surveys are often affected by poor awareness of the oceanographic environment in which the surveys are conducted.1Center for Coastal and Ocean Mapping/NOAA-UNH Joint Hydrographic Center, School of Marine Science and Ocean Engineering, University of New Hampshire, Durham, NH, United States.
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