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Day 3 - Multibeam Sonar


Day 3 - Multibeam Sonar

Written by:
Anthony Klemm
Hydrographer
United States National Oceanic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps)


I’m Anthony Klemm, a visiting hydrographer operating Celtic Explorer’s multibeam sonar. I am a lieutenant for the United States National Oceanic and Atmospheric Administration Commissioned Officer Corps (NOAA Corps), and very excited to participate in this cruise. I am currently assigned as an officer aboard NOAA Ship Thomas Jefferson, named after the third U.S. president, and founder of NOAA’s predecessor agency, the U.S. Coast Survey.

The plan is to transit from Galway to St. John’s, on the Canadian island of Newfoundland. On the way, we are mapping the seafloor using multibeam sonar, which is able to “sound” the depths down to at least 4500m. Because the multibeam is directed downward at an angle, the beams fan out, almost like a painter’s brush, painting a three dimensional model of the seafloor as the ship moves along. At these depths in the North Atlantic, we are able to see about 3.5km on each side of the ship.



The collecting and sharing of this multibeam sonar data exemplifies the Marine Institute’s dedication and resolve to map the ocean. Estimates vary, but there is general consensus that less than 20% of the ocean floor has been mapped. By making this data open an available, this bathymetry will add to the foundational knowledge for understanding global ocean systems. Bathymetry steers ocean circulation, provides the foundation for underwater habitats, and impacts vessel traffic and safety. It even defines the best surf spots. The more we know about ocean bathymetry, the more we know about all other ocean sciences.