Temporal and spatial dependence of a yearlong record of sound propagation from the Canada Basin to the Chukchi Shelf

Author Posting. © Acoustical Society of America, 2020. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 148(3),(2020): 1663, doi:10.1121/10.0001970.The Pacific Arctic Region has experienced decadal changes in atmospheric conditions, seasonal sea-ice coverage, and thermohaline structure that have consequences for underwater sound propagation. To better understand Arctic acoustics, a set of experiments known as the deep-water Canada Basin acoustic propagation experiment and the shallow-water Canada Basin acoustic propagation experiment was conducted in the Canada Basin and on the Chukchi Shelf from summer 2016 to summer 2017. During the experiments, low-frequency signals from five tomographic sources located in the deep basin were recorded by an array of hydrophones located on the shelf. Over the course of the yearlong experiment, the surface conditions transitioned from completely open water to fully ice-covered. The propagation conditions in the deep basin were dominated by a subsurface duct; however, over the slope and shelf, the duct was seen to significantly weaken during the winter and spring. The combination of these surface and subsurface conditions led to changes in the received level of the sources that exceeded 60 dB and showed a distinct spacio-temporal dependence, which was correlated with the locations of the sources in the basin. This paper seeks to quantify the observed variability in the received signals through propagation modeling using spatially sparse environmental measurements.This work was supported by the Office of Naval Research Ocean Acoustics Program (ONR OA322) under Grant Nos. N00014-15-1-2144, N00014-15-1-2119, N00014-15-1-2017, N00014-15-1-2068, N00014-15-1-2110, N00014-19-1-2721, N00014-15-1-2898, N00014-15-1-2806, and N00014-18-1-2140. The basin moored environmental data were supported by the ONR Arctic and Global Prediction Program (ONR AG322) under Grant No. N00014-15-1-2782. Mooring and hydrographic data were collected and made available by the Beaufort Gyre Exploration Program based at the Woods Hole Oceanographic Institution (http://www.whoi.edu/beaufortgyre) in collaboration with researchers from Fisheries and Oceans Canada at the Institute of Ocean Sciences. The ITP data were collected and made available by the ITP Program (Krishfield et al., 2008; Toole et al., 2011) based at the Woods Hole Oceanographic Institution (http://www.whoi.edu/itp). We acknowledge the use of imagery from the Worldview Snapshots application (https://wvs.earthdata.nasa.gov), part of the Earth Observing System Data and Information System (EOSDIS).2021-03-2