NOAA Ship Okeanos Explorer continued transiting northeast to our second operating area near the Cook Islands – specifically, just north of the Manihiki Plateau. We continue to map along the way, collecting valuable data in support of Marae Moana, the Cook Islands marine park. While mapping, one of the things we look at is backscatter. In physics, backscatter is the reflection of waves, particles, or signals back to the direction from which they came. For our purposes, it is the sound intensity that returns to the ship's sonars from the seafloor. The reflection of this sound intensity is driven by the acoustical properties of the seafloor surface. Hard surfaces, like rock, tend to return the sonar's sound energy better than softer bottom compositions, like mud. Therefore, measuring the strength of the sound returned from the seafloor can help us interpret what is on the seafloor (e.g., mud, rock, etc.). We can also learn about the roughness of the bottom or grain size. Backscatter data can also assist us with dive planning. Because these data give us an idea of what we can expect to see before we send down the remotely operated vehicle, we can maximize Deep Discoverer's bottom time by targeting the areas we are most interested in exploring.

Tune in tomorrow for our next dive!