Modeled physical oceanography of the New England Sea mounts during Summer 2024

Physical oceanography processes affecting underwater sound speed and acoustic propagation near the New England Seamounts during July and August 2024 are discussed. These processes impact underwater sound propagation through the generation, modification, and destruction of surface ducts and secondary sound channels, as well as modify the deep sound channel and convergence zone horizontal length scale. An additional factor is the presence of Gulf Stream, which serves as a boundary between cold Scotian Shelf waters to the north and warm Sargasso Sea water to the south. These water masses have different sound speed properties, so the variability of the Gulf Stream, thus these water masses, impacts sound speed. Results from real-time data assimilating models are analyzed, verified against in situ temperature and salinity vertical profiles from gliders, ships, and other sensors from a large field program. Model results supported field work in multiple ways: Assisting in daily planning of ocean-acoustic adaptive sampling missions; real-time acoustic modeling; and skillful prediction of cold water at 50–100 m depth originating several hundred kilometers away. These results demonstrate a capability for data-informed real-time ocean models to skillfully predict transient physical oceanographic features and their sound speed properties. Work supported by Office of Naval Research.