Grant: Alliance Grants

We aim to combine ultrasound and sonar expertise to develop a system using acoustic remote sensing methods to create local ocean sound speed profiles; that is measurements of how sound speed varies with depth. Accurate knowledge of local sound speed structure greatly enhances the performance of virtually all sonar systems. Sonar applications play a vital role in almost all marine activities, including fisheries research, commercial fishing, offshore oil and gas, and ocean surveying. Also, sound speed in the ocean serves as an indirect measure of temperature, which is crucial for physical and biological studies in oceanography. Canada has coasts on three oceans and as a result has extensive marine resources and industry; the marine sector contributes $36.1 billion annually to the Canadian economy (StatsCan, 2021). Clearly, understanding and monitoring ocean conditions are essential for responsible development of Canada's ocean resources.Operating on a completely different scale than in ocean application but utilizing essentially the same physical principles, ultrasound is used to provide images of tissue for medical applications. In most of those applications, knowledge of sound speed is critical to optimizing image quality. More recent research efforts are trying to extend the ultrasound sampling to detect changes of sound speed in tissue to help identify areas of disease. At Memorial University we will explore those same research results to make measurements of ocean temperature possible.In this work, we are proposing a new collaboration between medical researchers at Stanford University in California and our ocean acoustics research group at Memorial University to explore methods of sound speed estimation using acoustic methods. This cross disciplinary collaboration will benefit both groups by sharing different perspectives on a related measurement challenge.