Figure 3. Multifrequency echosounder system aboard the R/V Point Sur with four frequencies (18, 38, 70, 120 kHz) installed (left panel). Ascending (center panel) and descending (right panel) phase of the diel vertical migration of the sound scattering layer observed from 0000 to about 1300 UTC on July 29, 2021. The scattering layer can be seen rising from 500 meters (1,640 feet) in depth to 100 meters (328 feet) in depth, and then back down again. The bright horizontal line at 400 meters (1,312 feet) in the right panel is the reflection from the CTD rosette that was also operating an autonomous echosounder at depth with two different frequencies (38 and 200 kHz).
Multifrequency Echosounder System
Image courtesy of Exploring Migrating Deep-Sea Scattering Layers. Download largest version (jpg, 83 KB).

Figure 3. Multifrequency echosounder system aboard the R/V Point Sur with four frequencies (18, 38, 70, 120 kHz) installed (left panel). Ascending (center panel) and descending (right panel) phase of the diel vertical migration of the sound scattering layer observed from 0000 to about 1300 UTC on July 29, 2021. The scattering layer can be seen rising from 500 meters (1,640 feet) in depth to 100 meters (328 feet) in depth, and then back down again. The bright horizontal line at 400 meters (1,312 feet) in the right panel is the reflection from the CTD rosette that was also operating an autonomous echosounder at depth with two different frequencies (38 and 200 kHz).

Learn more