The influence of thermal stratification upon acoustic propagation: Impacts on fish detection

Session: 47. - Physical Processes in Lakes

Jing zhi Li, University of Toronto Scarborough, [email protected]
Mathew Wells, University of Toronto Scarborough, [email protected]

Abstract

In this talk we will review how speed of sound variations due to thermal stratification can lead to refraction of acoustic signals. A recent development in fisheries research has been the use of acoustic tags to track fish throughout the Great Lakes, and the number of tags and receivers has greatly expanded in the last 5 years. The speed of sound is primarily a function of water temperature, and Snell’s law implies that when there is a change of water temperature, the sound speed gradient will refract sound waves, and thus influencing the attenuation with distance. We will discuss what this implies for typical summer thermoclines in the lower Great lakes, where there is commonly strong thermal gradients of 1^oC /m in the thermocline.

1. Keyword
acoustics

2. Keyword
observing systems

3. Keyword
hydrodynamics