Measurements of ocean finestructure (with typical time scales of 15 min to 1 d, spacial scales of 10 to 100 m vertically and 1 to 10 km horizontally) are consistent with the measured variability in the transmission of acoustic signals through the ocean volume. The observations suggest that the statistics of acoustic fluctuations can be used to monitor the statistics of ocean finestructure. Further, fluctuations in the travel time are a measure largely of temperature fluctuations along the acoustic path, and the difference in reciprocal travel times is a measure of the component, along the path, of current and current shear. Such acoustic measurements give integrals along the paths, with the attendant advantages and disadvantages as compared with the traditional ‘spot’ measurements; precision promises to be comparable or better.
- Walter H. Munk
- Gordon O. Williams
