A comparison of measured and predicted broadband acoustic arrivals in Fram Strait

Abstract

Fram Strait is the only deep-water connection between the Arctic and the world oceans. On the eastern side, the northbound West Spitsbergen Current transports warm Atlantic water into the Arctic, while on the western side the southbound East Greenland Current transports sea ice and polar water from the Arctic to the Nordic Seas and Atlantic Ocean. Significant recirculation and intense small-scale mesoscale variability in the center of the Strait make it difficult to accurately measure ocean transports through the Strait. An acoustic system for tomography, glider navigation, and passive listening was installed in the central, deep-water part of the Strait during 2010–2012. The integral measurements of temperature provided by tomography and the spatial resolution of the glider data are complementary to the data from the long-term array of oceanographic moorings at 780 50’N. The oceanographic conditions and highly variable sea ice in Fram Strait provide an acoustic environment that differs from both the high Arctic and the temperate oceans and that results in complex acoustic propagation. Improved understanding of the measured acoustic arrivals through comparison with predictions based on available environmental data is important for development of tomographic inversion and assimilation techniques, for glider navigation, and for acoustic communications.