AGU: Geophysical Research Letters

 

Editors' Highlight

Underwater acoustics: Remote estimates of the sonic layer depth

Accurate use of underwater acoustic data, information critical to generating navigational charts and maps of the ocean floor, requires knowledge of sound speed profiles throughout the water column, in particular the near-surface depth at which sound speed is fastest. Called the sonic layer depth (SLD), this depth determines where sound waves refract; knowledge of SLD location is used to reduce errors in sonar surveys. Noting that direct observations of SLDs at all locations in the ocean are difficult to obtain, Jain et al. (2007) sought to determine whether remote observations could be used to determine SLDs. Using surface and measurements collected from moorings on the Arabian Sea and an artificial neural network (ANN), which is an information processing system of highly interconnected pathways inspired by the human brain, the authors estimated SLDs. Their estimates agree well with known vertical profiles of the Arabian Sea and are more accurate than previous methods used to estimate SLD remotely. The authors anticipate that instead of using data from moorings, future estimates can be generated by ANNs using satellite data.

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