Sea Technology

FEB 2018

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

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Page 29 of 52 February 2018 | ST 29 that have a long life, but vendors should still offer a peace-of-mind check for integrators since it is important to check when dealing with long-term data sets. For ex- ample, Turner Designs offers a solid reference standard that will not change, so integrators can be assured that if a change is observed, the change is with the instrument and not the reference material. This is the problem most users encounter when using solutions to check stability: Was it the solution or instrument that changed? The following are just a few examples of the issues that are encountered when integrating instruments with AUVs. Liquid Robotics' PacX Mission On November 17, 2011, Liquid Robotics launched four AUVs (Wave Gliders) from San Francisco on a mis- sion to cross the Pacific Ocean, two going to Japan and two to Australia. This mission, dubbed PacX, collected millions of data points and set a new Guinness World Record for the furthest distance traveled by an unmanned surface vehicle (7,939 nautical miles). Wave Gliders are surface vehicles that use wave power for thrust. The smallest waves can be used to propel the AUV forward, and the vehicle's heading can be changed by remotely controlling it from an operations facility. Each vehicle in the PacX mission carried identical scientific equipment including a CTD, weather station, wave sensor, cam- era and Turner Designs fluorometers. There were many interesting data sets collected along the way, one of which documented a mid-ocean bloom and another that showed the aftermath of a tropical cyclone. Mid-Ocean Bloom. The detection of open-ocean pri- mary productivity is a scientifically critical capability fa- cilitated by combining reliable fluorometry with AUVs. The two Wave Gliders carrying Turner Designs' fluoro- meters as they voyaged across the equatorial upwelling zone measured high-chlorophyll fluorescence responses. Tropical Cyclone Freda. On December 31, 2012 one of the Wave Gliders intersected with a tropical cyclone in the Coral Sea. Wind speeds were an average of 95 kt., resulting in 10-m waves. The AUV captured data throughout the event that shows the biological response after the cyclone had passed: estimated chlorophyll con- centrations increased, indicating bloom activity. Navocean HAB Mapping Harmful algal blooms (HABs) significantly affect ecosystem health, resulting in mass fish mortalities and threatening mammals and seabirds. They also prove to be a threat to the public, with numerous recorded ac- counts of human death from ingestion of contaminated finfish and shellfish. Combating HABs is best approached through development of HAB-specific instrumentation and integrations with AUVs, such as the Nav2 autono- mous vehicle manufactured by Navocean, based in Seat- tle, Washington, to conduct preemptive ocean-mapping exercises that will provide information on HAB distribu- tion or "hot spots." Deploy and recover with confidence. For over 35 years our subsea buoyancy product line has been the first choice amongst ocean engineers for projects from near surface to full ocean depth. +1.207.502.1400 come up goes down must What

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