Upward looking sonar
An upward looking sonar (ULS) is a sonar device pointed upwards looking towards the surface of the sea. It is used for similar purposes as downward looking sonar, but has some unique applications such as measuring sea ice depth and concentration or measuring air entrainment from bubble plumes during rough seas.
- Connolley, William (29 May 2005). "Stoat: Sea ice: What I do in my spare time :-)". Stoat. Retrieved 19 October 2017.