Showing papers on "iRobot Seaglider published in 2008"

Seaglider observations of blooms and subsurface chlorophyll maxima off the Washington coast

Abstract: From September 2003 to December 2007, autonomous, underwater Seaglider continuously ran a V-shaped transect off Washington State from about 200-m water depth (i.e., at the break between the shelf and slope) to offshore waters with depths >2700 m. Seaglider visited the offshore vertex at 47°N, 128°W, where our observations concentrated, approximately monthly. Seaglider measured temperature, conductivity, and dissolved oxygen to 1000 m and also recorded chlorophyll a (Chl a) fluorescence and particulate optical backscatter to 150 m. Distinct interannual variation was documented in timing and depths of winter mixing, transition to a shallow summer pycnocline, and onset of mixed-layer erosion in autumn. Chl a concentrations estimated from fluorescence were directly comparable among the seven laboratory-calibrated sensors used, but their estimates exceeded concurrent, satellite-derived concentrations by a factor of three. Seaglider optical profiles enabled interpretation of satellite imagery by revealing that the apparent autumn bloom after destratification was instead a vertical redistribution of phytoplankton from the subsurface maximum to a depth where they could be observed by satellites. Results of 4 yr of sampling within 25 km of the vertex demonstrate the value of gliders in ocean observing and their capability to carry out multiyear, fully autonomous operations under any sea state. The true power of glider programs will be realized in combination with other measurement platforms, including larger spatial coverage by satellites and more comprehensive biogeochemical measurements from moorings and occasional ship-based sampling.

Seaglider observations of variability in daytime fluorescence quenching of chlorophyll-a in Northeastern Pacific coastal waters

Abstract: . The use of new autonomous and Lagrangian platforms (e.g. gliders, drifters, etc.) has revolutionized sampling of the ocean. The incorporation of in vivo chlorophyll-a fluorometers into these platforms for characterizing chlorophyll-a concentrations and phytoplankton biomass has reinforced the need for a thorough understanding of the variability and biases associated with basic fluorescence measurements. Seaglider, a long-range autonomous glider, has been deployed routinely in Northeast Pacific waters off the Washington coast, USA. Measurements of chlorophyll-a fluorescence (proxy for chlorophyll-a concentration) and optical backscattering (proxy for particle concentration) were collected on the continental shelf and along a V-shaped transect that extended 200 km from the continental shelf into deep oceanic waters. Daytime fluorescence quenching (i.e. the reduction in the fluorescence quantum yield often observed during daylight hours) could be detected throughout the dataset, with near-surface daytime fluorescence quenched by as much as 80% during summer. Quenching was observed throughout the region, at all times of year, and to depths greater than 50 m. The degree of quenching was positively correlated with incoming solar radiation and the observed pattern was remarkably similar to what has been observed in other areas, suggesting some degree of universality for the underlying relationship.

Autonomous Underwater Vehicles: A Transformation in Mine Counter‐Measure Operations

Abstract: (2008). Autonomous Underwater Vehicles: A Transformation in Mine Counter‐Measure Operations. Defense & Security Analysis: Vol. 24, No. 3, pp. 247-266.

Think on the development in autonomous underwater vehicles

Abstract: Application foreground of autonomous underwater vehicles is very wide in ocean exploitation and naval affairs.Technology of autonomous underwater vehicle is technical field that is developed by every country in the world.In this paper the development of autonomous underwater vehicles abroad is introduced briefly.The key techniques those should be focused our attention on and the several suggestions are put forward.

Nessie III Autonomous Underwater Vehicle for SAUC-E 2008

Abstract: The Nessie III autonomous underwater vehicle was designed and built in the Ocean Systems Laboratory at Heriot-Watt University to compete in the 2008 Student Autonomous Underwater Challenge ‐ Europe competition. Employing a robust, modular hardware and software design the vehicle was able to successfully complete all of the tasks set out in the competition, and will serve as an excellent platform for further research and development. This paper describes the Nessie III autonomous underwater vehicle (AUV) developed at the Ocean Systems Laboratory at Heriot-Watt University. The vehicle was designed to compete in the 2008 Student Autonomous Underwater Challenge Europe (SAUC-E) competition held at the IFREMER deep wave basin near Brest, France. Section II describes the vehicle hardware, and section III covers the software architecture.