Acoustic Thermometry of Ocean Climate (ATOC) An acoustic network in the Northeast Pacific Ocean measures basin-scale ocean temperature over time scales of several years. The arrival times of signals propagating over acoustic paths as long as 5000 km are measured to within 0.006 second, corresponding to range- and depth-averaged temperature measurements that are accurate to within 0.01°C. Given a suitable long time series, the ATOC network will detect climate trends in the ocean.

Comprehensive Test Ban Treaty Various geophysical technologies are used to monitor for compliance with the treaty, including hydroacoustics. Monitoring low-frequency water-borne sound waves, some traveling thousands of kilometers, allows detection of nuclear weapons test ban violations.

Long-range Ocean Acoustic Propagation Experiment (LOAPEX) The experiment suspended an acoustic source from the R/V Melville at several locations in the eastern Pacific, and utilized the North Pacific Acoustic Laboratory (NPAL) signal receiver assets that were installed by APL-UW during the Acoustic Thermometry of Ocean Climate (ATOC) demonstration. Among other objectives, this experiment was conducted to study the evolution, with distance, of the acoustic arrival pattern and to produce a thermal map to the Northeast Pacific Ocean.

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