Predicting ocean motions and underwater sounds

Paper: "Coupled Ocean'Acoustic Prediction of Transmission Loss in a Continental Shelfbreak Region: Predictive Skill, Uncertainty Quantification, and Dynamical Sensitivities". Ocean variability - the perpetual changing of currents, temperatures, salinity and the contours of the seafloor - alters the way sound travels through the water. A new analysis of how this variability affects sound waves could make it easier for Navy submarines to evade detection or for remotely operated underwater vehicles, like those used to combat the recent Macondo oil well spill in the Gulf of Mexico, to maneuver more accurately. It could also aid in basic oceanographic and climate research by helping to calibrate systems for using sound waves to measure ocean properties such as temperature and seafloor topography. The analysis was carried out by MIT researchers in collaboration with Taiwanese and Woods Hole Oceanographic Institution scientists. Using both theoretical computer models and on-site experiments off Taiwan and Kauai, they found unexpected changes in the way ocean and sound waves interact when they are emitted near the edge of a continental shelf, where the average slope of the seafloor changes abruptly. For the first time, they were able to make integrated ocean and acoustics predictions of how sound waves would propagate at a given time and location, and of the degree of uncertainty in those predictions, and then verified those predictions with actual acoustic measurements.