Current direction, bathythermograph (xbt), CTD, and other data from moored current meter casts and other instruments in the Northwest Atlantic Ocean (limit-40 W) and North American Coastline-South as part of the North Carolina FRontal Eddy Dynamics Experiment (FRED) project, 1987-05-07 to 1987-11-01 (NCEI Accession 8900181)

Current direction, bathythermograph (xbt), CTD, and other data were collected using moored current meter casts and other instruments in the Northwest Atlantic Ocean (limit-40 W) and North American Coastline-South from May 7, 1987 to November 1, 1987. Data were submitted by Science Applications, INC - Raleigh NC as part of the North Carolina FRontal Eddy Dynamics Experiment (FRED) project. Data has been processed by NODC to the NODC standard F015- Current Meter Data, F156- Drifting Buoy, C116/C118- Bathythermograph XBT, and C125- UBT formats.

The F015 format is used for time series measurements of ocean currents. These data are obtained from current meter moorings and represent Eulerian method of current measurement, i.e., the meters are deployed at a fixed point and measure flow past a sensor. Position, bottom depth, sensor depth, and meter characteristics are reported for each station. The data record comprises values of east-west (u) and north-south (v) current vector components at specified date and time. Current direction is defined as the direction toward which the water is flowing with positive directions east and north and negative directions west and south. Data values may be subject to averaging or filtering and are typically reported at 10-15 minute time intervals. Water temperature, pressure, and conductivity or salinity may also be reported. A text record is available for optional comments.

The F156 format is used for time series data on ocean circulation determined by the tracking of drifting buoys, drogues, or other instrumented devices as they are carried with the flow. Movement is reported as point-to-point geographic locations determined by shore-based, surface ship, aircraft, or satellite observations. Data from both ocean currents and ice movement can be reported in this format over time periods ranging from minutes to months. Directions and speeds between individual observations may be computed from these data and presented in graphic or summary listing form to provide information on circulation patterns and mass transport in offshore and near- shore regions. Platform name (for platform acquiring data or deploying device), drogue characteristics, start and end positions and times, and observation frequency (if constant time interval) are reported for each series of observation. Other surface meteorological or oceanographic parameters (e.g., water temperature and salinity, air temperature and pressure, wind, waves) and subsurface data (depth, pressure, temperature) may also be reported. Text records may be used to report general comments or to describe individual drogue observations.

The C116 and C118 format contains temperature-depth profile data obtained using expendable bathythermograph (XBT) instruments. Cruise information, position, date and time were reported for each observation. The data record was comprised of pairs of temperature-depth values. Unlike the MBT Data File, in which temperature values were recorded at uniform 5 m intervals, the XBT data files contained temperature values at non-uniform depths. These depths were recorded at the minimum number of points ("inflection points") required to accurately define the temperature curve. Standard XBTs can obtain profiles to depths of either 450 or 760 m. With special instruments, measurements can be obtained to 1830 m. Prior to July 1994, XBT data were routinely processed to one of these standard types. XBT data are now processed and loaded directly in to the NODC Ocean Profile Data Base (OPDB). Historic data from these two data types were loaded into the OPDB.

The UBT (C125) format contains temperature-depth profile data obtained using expendable bathythermograph (XBT) instruments. Cruise information, position, date and time were reported for each observation. The data records are comprised of pairs of temperature-depth values. Depths are selected by the originator - usually at standard horizons or some fixed interval. Standard XBTs can obtain profiles to depths of either 450 or 760 m. Special instruments permitted measurements to be obtained to 1830 m.

Tags: oceanography
Organization: National Oceanic and Atmospheric Administration, Department of Commerce