Ocean Acoustic Tomography and Telemetry

摘要

The purpose of ocean tomography is to measure the (time- varying) speed of soundc(x,y,z;t) and ocean currents u(x,y,z;t) in three dimensions. The oceanographers can further transform these, with other information, into three-dimensional temperature and heat-flux fields. The method of Ocean Acoustic Tomography is to send acoustic timing signals, from each of a number of transmitters to a number of receivers these being spaced perhaps 250 km to 1250 km apart. At such range the sound from any specified transmitter to any specified receiver will travel over several distinctly different identified raypaths, perhaps 5 to 25. As the ocean propagation conditions change, the pattern of changes in the travel times along all the identified raypaths from all transmitters to all receivers can be mathematically 'inverted' to estimate the three dimensional sound speed c(x,y,z;t).