Sea Technology

JUL 2017

The industry's recognized authority for design, engineering and application of equipment and services in the global ocean community

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Page 37 of 68 July 2017 / st 37 attached to an overboard pole and deployed from an an- chored research vessel. The standard target was suspended under the AZFP transducer. For comparison, a Simrad EK-60 split-beam echosounder operating at 120 kHz was mounted to the same pole and used to confirm target strengths for the sphere, while also providing positioning information of the target relative to the single-beam AZFP transducer. The cali- bration was repeated at several transmission pulse lengths that may be used during missions of various water depth ranges. AZFP signal gain offsets were adjusted so that the observed target strength matched theoretical target strength at 200 kHz, nominally -38.9 dB. Noise profiles under normal glider operations revealed +6 dB signal over background noise at ranges comparable to other 200-kHz echosounders. Backscatter and target strengths expected from zooplankton and other low-energy scatterers (-90 dB) would be detected to a range of 70 m. Fish and other higher energy scatterers (more than -60 dB) would be detected at ranges greater than 100 m from the glider. Pilot Glider Mission A 14-day pilot mission was conducted along a pipeline in the northeast Gulf of Mexico on the West Florida Shelf Slocum glider deployed for pilot mission in the eastern Gulf of Mexico. (Photo Credit: Chad Lembke, USF) Custom cable engineering for the world's most mission-critical Marine and Subsea applications.

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