Modelling of sound propagation across the Arctic Ocean using oceanographic fields and oceanographic data

During the coordinated arctic acoustic thermometry experiment (CAATEX), two acoustic sources transmitted 35 Hz binary m-sequences in a yearlong experiment. The signals were transmitted across the Arctic Ocean and detected at distances up to 2700 km. The aim was to make measurements similar to those carried out in 1994 and 1998, to investigate the changes in sound propagation due to changes in the ocean temperature, ocean stratification, and thinning of the sea ice. Changes in propagation conditions over the last decades were investigated using time-series of data from ocean reanalysis, as well as available oceanographic data along the transect. Range-dependent fields were constructed and used as environmental input to acoustic models to produce time series of arrival times and vertical arrival structure. This approach allows for an examination of the sensitivity of low-frequency sound propagation to both vertical and large-scale horizontal changes in the ice-ocean environment. The predicted time series of acoustic travel times and arrival structure will be presented and compared with the observations.