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Nortek Time Series

Data files for Nortek Current Profilers are described here. Ancillary data (e.g., temperature, pitch, roll) are also available independently.

Revision History

  1. 201011XX: Beta product released

Formats

The formats available and basic information will be described here. Also include post-processing requirements, as necessary: Software or files needed for user to use data product

PRF

This binary format is specific to the manufacturer. When using Nortek data acquisition software, data is normally stored in this way. Although we use custom-built drivers to communicate with our instruments, we can use the raw data in the log file to produce the PRF file which can be interpreted by Nortek post-processing software (e.g., for the Nortek HR-Profilers click here.

To produce the file, the following requirements apply:

  • A new prf file is started at the start of each day, when the maximum records per file is exceeded (currently set as 2880), or when the driver is restarted (this should account for configuration changes, site changes, etc).
  • Only records with valid checksums are included.
  • The instrument date/time field is replaced by the NEPTUNE timestamp at the beginning of the log file (since this timestamp is more accurate than the instrument clock), and the checksum is recalculated.
  • instrument hardware, head and user configuration strings are inserted as the first three lines of the PRF file.

This format is further described in the manufacturer's System Integrator Guide.

Example: BH_POD2_AD2M_20101018T160041.704.prf

MAT - Coming Soon

MAT files (v7) can be opened using MathWorks MATLAB 7.0 or later. The file contains four structures: meta, data, config, and units.

meta: structure containing the following metadata fields.

  • deviceID: A unique identifier to represent the instrument within the NEPTUNE Canada observatory.
  • creationDate:Date and time (using ISO8601 format) that the data product was produced. This is a valuable indicator for comparing to other revisions of the same data product.
  • deviceHeading: Obtained at time of deployment (exception: for Device ID 13051, this field is NaN since this ADCP is on a mooring and does not have a fix heading).
  • siteName: Name corresponding to its latitude, longitude, depth position.
  • deviceName: A name given to the instrument.
  • deviceCode: A unique string for the instrument which is used to generate data product filenames.
  • locationName: The node of the NEPTUNE Canada observatory. Each location contains many sites.
  • samplingPeriod: Sampling rate of the instrument in seconds.
  • depth: Obtained at time of deployment.
  • lat: Obtained at time of deployment.
  • lon: Obtained at time of deployment.
  • dataProductVer: Version of data product.

data: structure containing the ADCP data, having the following fields.

  • range: vector of distance to start of each bin
  • corr: 3D matrix, correlation time-series for each bin
  • velocity: 3D matrix, corresponds directly to output of instrument and so depends on configuration coordinate system
  • compassHeading: vector, magnetic compass heading time-series
  • pitch: vector, pitch time-series
  • roll: vector, roll time-series
  • time: vector, timestamp in datenum format (obtained from time the reading reached the shore station)
  • temperature: vector, temperature time-series
  • pressure: vector, pressure time-series
  • cellDepth: vector, starting depth of each cell calculated from range and deployment depth
  • soundSpeed: vector or constant (depending if configured to be fixed or computed)
  • u: 2D matrix, East velocity relative to True North
  • v: 2D matrix, North velocity relative to True North
  • w: 2D matrix, Upward Velocity

config: structure containing Nortek Aquadopp Profiler configuration details. For details about the configuration parameters, refer to the manufacturer documentation.

units: structure containing unit of measure for fields in structures above. For instance, units.pressure='decibar'.

Example:

  • avgInterval: average interval
  • beamAngle: angle of beams
  • blankingDistance: distance from the sensor head to the start of the first measurement cell. See Nortek forum discussion for calculation details.
  • boardFrequency: frequency
  • cellSize: size of each cell. See Nortek forum discussion for calculation details.
  • coordSys: coordinates system of raw data (BEAM, XYZ or ENU)
  • headFrequency: frequency
  • nbeams: number of transducers/beams.
  • ncells: number of cells
  • orientation: Up or Down indicates the direction transducers are facing
  • velocityScaling: scaling for velocities from raw data, dependent on configuration

Discussion

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