Ocean currents quite literally drive the vast majority of thermal energy around the world. Understanding those flows is important, both for understanding global climate change and for those working in the oceans, such as the Gulf of Mexico, where strong loop currents can literally halt operations.

While surface currents can be measured with radar or satellite, measuring the flow velocities through the full water column, to create 3D models of the ocean, is more difficult.

Our Pressure Inverted Echo Sounder (PIES) exploits the correlation between two-way travel time of sound through water, from the seabed to the surface, and the thermal structure of water. Combined with conductivity, temperature, and depth (CTD) data, these allow large scale observation of ocean currents.

PIES is also capable of monitoring sea state (and by inference wind-speed) as periods of low sea state are characterised by larger, stronger and more specular reflection from the surface, while weaker, more diffuse returns result from high sea states.