California Shakedown Cruise 2011: Exploring California's National Marine Sanctuaries
EX1101 was the NOAA Ship Okeanos Explorer’s first cruise of the 2011 field season. It was focused on ship shakedown and sonar patch testing in order to prepare for the coming field season. It provided an opportunity to get the ship underway and ensure that all of its systems and equipment were fully operational prior to integration of the ROV on board. Additionally, the cruise provided an opportunity to conduct bathymetric mapping to support the work of other NOAA offices and to select specific dive targets for use in ROV testing during subsequent cruises.
Getting the ship ready for fieldwork after several months in dry dock is a complex challenge. The shakedown cruise provides an opportunity for the ship’s crew to ensure that all the equipment, machinery and gear are functional, seaworthy, and operating safely. It also provides an opportunity for the ships scientists to test and assess the performance of scientific equipment and instrumentation. During this cruise, the EM 302 (30 Khz) multibeam sonar, EA 600 (12 kHz) singlebeam sonar, and Knudsen sub-bottom profiler were tested.
This cruise also afforded the opportunity to conduct mapping in vicinity of Southern California after the ship shakedown objectives were met. The majority of the areas mapped were requested by other NOAA offices and integrated within the overall mapping shakedown objectives of the cruise. For this cruise, on board mapping personal collaborated with scientists from the Office of National Marine Sanctuaries (ONMS) to map the areas within Monterey Bay National Marine Sanctuary (MBNMS),the Channel Islands National Marine Sanctuary (CINMS), and an offshore area in the vicinity of San Juan Seamount. Additionally, the Center for Coastal Environmental Health and Bimolecular Research within the National Ocean Service, and the Southwest Fisheries Science Center within National Marine Fisheries Service jointly requested surveys over Hancock Seamount and “109” Seamount. Additionally, one archeological target was investigated within Gulf of the Farallones National Marine Sanctuary.
EM 302 multibeam sonar performance was evaluated during this cruise and determined to be satisfactory. Given that environmental and instrumental errors impact portions of the swath coverage of the multibeam sonar differently, an optimal method for evaluating system performance is to run a number of overlapping survey lines in a procedure know as a patch test. After imaging the same “patch” of seafloor multiple times differences in each survey line can be isolated and attributed to environmental or instrumental errors which can then be documented and in some cases corrected for. This detailed assessment of the multibeam sonar at the start of the field season is necessary to document system capabilities, optimize settings for the season, and diagnose any problems arising from changes in hardware or software over the winter dockside period.
Multibeam Bathymetric Data:
- NOAA's National Geophysical Data Center (NGDC) –
NOAA Ship Okeanos Explorer 2011 Field Season Data Sets.
- NOAA Office of Marine and Aviation Operations (OMAO) –
NOAA Ship Okeanos Explorer
- University of New Hampshire, Center for Ocean & Coastal Mapping –
- NOAA Fisheries Southwest Fisheries Science Center (SWFSC) –
- NOAA Office of National Marine Sanctuaries (ONMS) –