Acoustic instrumentation

Acoustic data from ship born echo sounders (Simrad EK60) is used to capture particle and biological distribution inside and around the eddies. The echo sounder is mounted in a downward looking direction in a drop keel to reduce noise and disturbance from the sea surface.

Data is typically collected with a ping rate of one ping pr. Second. But dependent on depth this can be adjusted. With a dynamic range of around 150 dB and low noise level the EK60 has the ability to detect weak scattered at large distances. This is essential for mapping the whole biological distribution around and inside Eddies.

The figure underneath shows an echogram of an Eddie. The depth is along the y axis and starts at 16 m and goes down to a depth of 1155 m. The x axis shows the horizontal distance and is around 64 km. Color scale is from -94 to -30 dB, where white is <-94 dB.