Tripods were deployed at three sites along the outer perimeter of the shoal. Mounted on the tripods were instruments to measure surface waves, pressure, current velocity, bottom turbulence, suspended-sediment profiles, and sea-floor sand-ripple bedforms; one tripod also held a visual camera system. The measurements will be used to explore the oceanographic and sediment-transport processes responsible for maintaining the offshore sand shoal. For more information see <http://quashnet.er.usgs.gov/data/2009/09003/> and <http://quashnet.er.usgs.gov/data/2009/09014/>
The North Site had three instrument deployments:
North Flobee at 35.17863N, 75.42292W at a water depth of 14.7 meters - instruments include Acoustic Doppler Current Profile (ADCP), Acoustic Doppler Velocimeters (ADVs), Optical Backscatter Sensors (OBSs), Acoustic Backscatter Sensor System (ABSS), Pulse-Coherent Acoustic Doppler Profiler (PCADP), Sontek hydra system, Seatech transmissometers, Paroscientific (Paros) Pressure Sensors, a Sea-Bird SEACAT, and a Sea-Bird MicroCAT.
North Minipod at 35.1783° N, 75.423355° W at a water depth of 14.8 meters - instruments include ADCP, time-series visual image camera with flash, pencil beam and rotating sonar imaging system, Sea-Bird SEACAT, transmissometer, laser in situ scattering and transmissometer instrument (LISST), and an Aquadopp Acoustic Profiler.
North Surface mooring at 35.177867N, 75.422617W at water surface - instruments include ARGOS (Seimac CML) and Iridium (Xeos melo) satellite beacons on the buoys to track position, a Sea-Bird SEACAT, a Sea-Bird MicroCAT and a pressure and temperature sensor (PT).
South Sites with two deployments:
South Flobee at 35.12958N, 75.49204W at water depth 14.0 meters - instruments include ADCP, ADVs, OBSs, an ABS system, a PCADP, Sontek hydra system, Seatech transmissometers, Paros pressure sensors, a Sea-Bird SEACAT, and a Sea-Bird MicroCAT.
South Surface Mooring at 35.12895N, 75.49187W at water surface - instruments include ARGOS (Seimac CML) and Iridium (Xeos melo) satellite beacons on the buoys to track position, a Sea-Bird SEACAT, and a PT.
Tip Micropod at 35.098985N, 75.376055W at water depth 23.7 meters - instruments include upward-looking ADCP, Sea-Bird SEACAT, and Seatech transmissometer.
The instruments were deployed and recovered aboard the R/V Connecticut, a research vessel owned and operated by the University of Connecticut. Ellyn Montgomery is the contact for this process step and the subsequent process step.
Data processing was conducted using the proprietary software for each instrument, and (or) specialized software developed by the USGS. The proprietary software was often used to download data from the instruments and export the data to ASCII-files. Post-processing of the raw binary or ASCII files was accomplished using USGS software developed in the MATLAB (<http://www.mathworks.com/>) programming language. Most MATLAB M-files used for post-processing are available via the World Wide Web (WWW) (links provided). Those that are not available via the WWW are included in this report (see the Matlab m-files page available in <https://pubs.usgs.gov/of/2011/1156/>).
Data were first decoded and calibrated from instrument-specific formats and units to the EPIC-standard netcdf format (<http://www.pmel.noaa.gov/epic/>) and scientific units. Data were carefully checked for instrument malfunctions and then edited. The beginning and end of each data series were truncated to remove data collected out of water. The data were carefully checked at each stage of processing. After final editing, the best basic version of the data file includes all variables recorded at the basic sampling interval. Best basic versions of all data files in netcdf format are included in this report.
These data have been edited to remove outlying points and data recorded when the instruments were out of the water before and after deployment.
Biological fouling often degrades acoustical and optical data after several months of deployment. Organisms grow on the instrument transducers and gradually block acoustical pulses and light transmission, which results in a gradual upward drift of the beam attenuation coefficient. Care has been exercised to remove most data that have been affected by biofouling.
There was significant tilt of the ADCP at the North Flobee site when the tripod tipped in mid April. The velocity data have been removed for this latter portion of this ADCP file, but pressure and temperature data are available for the whole period. A change in the deployment depth at the Tip Micropod site resulted in data that did not reach the surface for that site. All data should be used and interpreted with care.
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.