What is 'acoustic tomography' used for in oceanography?

Acoustic tomography is utilized in oceanography primarily for measuring ocean temperatures over large distances. The technique involves sending sound waves through the water and analyzing how they are affected by the temperature variations in the ocean. The speed of sound in seawater is influenced by its temperature, salinity, and pressure. By sending acoustic signals through the ocean and measuring the time it takes for them to travel between specific points, researchers can infer temperature distributions over thousands of kilometers.

This method allows for the collection of extensive data on the ocean's thermal structure, which is vital for understanding ocean circulation, climate patterns, and heat distribution. Because sound travels faster in warmer water, the travel time of acoustic signals can serve as an indirect measure of temperature differences across large areas of the ocean. This capability is crucial for monitoring and modeling oceanographic conditions in a way that would be difficult to achieve with traditional methods, which often rely on point measurements.

Other options, while they pertain to different aspects of ocean studies or monitoring, do not capture the primary application of acoustic tomography in effectively mapping temperature patterns across vast oceanic regions.