- Ships use echo sounders, which emit sound waves and measure the time it takes for them to bounce off the seafloor and return.
- The depth can then be calculated using the speed of sound in water and the time taken for the sound waves to travel down and back.
Pressure sensors:
- Submarines and other submersibles measure depth using pressure sensors.
- As they descend, the pressure of the water increases, and this increase can be calibrated to determine depth.
Satellite altimetry:
- Satellites measuring the height of the sea surface can be used to infer the depth of the water.
- By measuring the time delay between the radar pulse and its return, the height of the sea surface can be calculated.
- This data is then used to create maps of the ocean's topography, including water depths.
