Inferring subsurface sound speed near the Gulf Stream by combining satellite altimetry with a climatology from underwater glider observations

The Gulf Stream separates cooler, fresher waters of subpolar origin from warmer, saltier subtropical waters, with a notably deeper sound speed minimum on the warm side of the front. North and east of its separation from the continental margin at Cape Hatteras, the Gulf Stream meanders substantially, leading to large variability in acoustic properties on time scales of days to weeks. Despite its varying position and orientation, the structure of the Gulf Stream front is known to be quite stable. Here, satellite altimetry is used to determine the location and orientation of the Gulf Stream at particular times, and a seasonal, stream-coordinate climatology developed from nearly a decade of underwater glider sampling is used to infer corresponding subsurface sound speed structure. Resulting predictions are compared to measured sound speed profiles and predictive skill is compared to an operational numerical simulation.