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Nortek Profiler Time Series

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

Revision History

  • 20150226: Change range to be to the beam centre, add bin mapping to correct velocities and range for tilt
  • 20150202: Heading correction rework (affecting ENU / uvw velocities): improve handing of mobile sensors, autonomous deployments and better documentation of processing was done to the data.
  • 20111019: Initial NetCDF, CF1.5 compliant product released.
  • 20110302: Correction to algorithm for obtaining ENU (with respect to true North velocities). If instrument is mobile, a combination of instrument compass and local magnetic declination is used. If instrument is fixed position, the orientation determined at instrument deployment is used.
  • 20110110: Initial MAT product released
  • 20101130: Initial PRF product released
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Formats

This data is available in manufacturers' raw binary data files (VEC / VNO / AQD / PRF), and parsed and processed time series data files (MAT and NETCDF). Content descriptions and example files are provided below.

To produce these files, the following requirements apply:

  • A new file is started at the start of each day, when the maximum records per file is exceeded (currently set as 2880 for PRF and 43200 for MAT), 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 and important parameters are parsed into MAT file. However, any data existing previous to accompanying configuration details being saved in the database cannot be interpreted (earlier than Fall 2009).
VEC / VNO / AQD / PRF

These very similar binary formats are specific to Nortek acoustic devices. 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 these files.

VEC is the format for Nortek Vector Current Meters, VNO is the format for Nortek Vectrino Current Meters, AQD is the format for Nortek Aquadopp Current Meters, PRF is the format for Nortek ADCPs, both the Aquadopp Current Profiler and the Aquadopp-HR Current Profiler. Go to each of those links for the appropriate manufacturers software for each. Nortek post-processing software, such as Surge will also read these formats, see here for downloads (some require license): http://www.nortek-as.com/en/support/software

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

Example: BH_POD2_AD2M_20101018T160041.704.prf

MAT

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

Meta: a structure array containing the following metadata fields:

  • deviceID: A unique identifier to represent the instrument within the Ocean Networks Canada data management and archiving system.
  • 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.
  • deviceName: A name given to the instrument.
  • deviceCode: A unique string for the instrument which is used to generate data product filenames.
  • deviceCategory: Device category to list under data search ('Echosounder').
  • deviceCategoryCode: Code representing the device category. Used for accessing webservices, as described here: API / webservice documentation (log in to see this link).
  • lat: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site latitude and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure..
  • lon: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site longitude and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure.
  • depth: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site depth and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure.
  • deviceHeading: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site heading and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure.
  • devicePitch: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site pitch and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure.
  • deviceRoll: Fixed value obtained at time of deployment. Will be NaN if mobile or if both site roll and device offset are null. If mobile, sensor information will be available in mobilePositionSensor structure.
  • siteName: Name corresponding to its latitude, longitude, depth position.
  • locationName: The node of the Ocean Networks Canada observatory. Each location contains many sites.
  • stationCode: Code representing the station or site. Used for accessing webservices, as described here: API / webservice documentation (log in to see this link).
  • dataQualityComments: In some cases, there are particular quality-related issues that are mentioned here.
  • MobilePositionSensor: A structure with information about sensors that provide additional scalar data on positioning and attitude (latitude, longitidue, depth below sea surface, heading, pitch, yaw, etc).

    • name: A cell array of sensor names for mobile position sensors. If not a mobile device, this will be an empty cell string.
    • sensorID: An array of unique identifiers of sensors that provide position data for mobile devices - this data may be used in this data product.
    • deviceID: An array of unique identifiers of devices that provide position data for mobile devices - this data may be used in this data product.
    • dateFrom: An array of datenums denoting the range of applicability of each mobile position sensor - this data may be used in this data product.
    • dateTo: An array of datenums denoting the range of applicability of each mobile position sensor - this data may be used in this data product.
    • typeName: A cell array of sensor names for mobile position sensors. If not a mobile device, this will be an empty cell string. One of: Latitude, Longitude, Depth, COMPASS_SENSOR, Pitch, Roll.
    • offset: An array of offsets between the mobile position sensors' values and the position of the device (for instance, if cabled profiler has a depth sensor that is 1.2 m above the device, the offset will be -1.2m).
    • sensorTypeID: An array of unique identifiers for the sensor type.
    • correctedSensorID: An array of unique identifiers of sensors that provide corrected mobile positioning data. This is generally used for profiling deployments where the latency is corrected for: CTD casts primarily.
  • deploymentDateFrom: The date of the deployment on which the data was acquired.
  • deploymentDateTo: The date of the end of the deployment on which the data was acquired (will be NaN if still deployed).
  • samplingPeriod: Sample period / data rating of the device in seconds, this is the sample period that controls the polling or reporting rate of the device (some parsed scalar sensors may report faster, some devices report in bursts) (may be omitted for some data products).
  • samplingPeriodDateFrom: matlab datenum of the start of the corresponding sample period (may be omitted for some data products).
  • samplingPeriodDateTo: matlab datenum of the end of the corresponding sample period (may be omitted for some data products).
  • sampleSize: the number of readings per sample period, normally 1, except for instruments that report in bursts. Will be zero for intermittent devices (may be omitted for some data products).
  • SamplePeriodSensor: A structure array with an entry for each scalar sensor on the device (even though this metadata is for complex data products that don't use scalar sensors).

    • sp: sample period in seconds (array), unless sensorid is NaN then this is the device sample period
    • dateFrom: array of date from / start date (inclusive) for each sample period in MATLAB datenum format.
    • dateTo: array of date to / end date (exclusive) for each sample period in MATLAB datenum format.
    • sampleSize: the number of readings per sample period (array). Normally 1, except for instruments that report in bursts. Will be zero for intermittent devices.
    • deviceID: array of unique identifiers of devices (should all be the same).
    • sensorID: array of unique identifiers of sensors on this device.
    • isDeviceLevel: flag (logical) that indicates, when true or 1, if the corresponding sample period/size is from the device-level information (i.e. applies to all sensors and the device driver's poll rate).
    • sensorName: the name of the sensor for which the sample period/size applies (much more user friendly than a sensorID).
  • citation: a char array containing the DOI citation text as it appears on the Dataset Landing Page. The citation text is formatted as follows: <Author(s) in alphabetical order>. <Publication Year>. <Title, consisting of Location Name (from searchTreeNodeName or siteName in ONC database) Deployed <Deployment Date (sitedevicedatefrom in ONC database)>. <Repository>. <Persistent Identifier, which is either a DOI URL or the queryPID (search_dtlid in ONC database)>. Accessed Date <query creation date (search.datecreated in ONC database)>
  • Attribution: A structure array with information on any contributors, ordered by importance and date. If an organization has more than one role it will be collated. If there are gaps in the date ranges, they are filled in with the default Ocean Networks Canada citation. If the "Attribution Required?" field is set to "No" on the Network Console then the citation will not appear. Here are the fields:
    • acknowledgement: the acknowledgement text, usually formatted as "<organizationName> (<organizationRole>)", except for when there are no attributions and the default is used (as shown above).
    • startDate: datenum format
    • endDate: datenum format
    • organizationName
    • organizationRole: comma separated list of roles
    • roleComment: primarily for internal use, usually used to reference relevant parts of the data agreement (may not appear)

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

  • time: vector, timestamp in datenum format (obtained from time the reading reached the shore station)
  • range: vector of distance to each bin centre. If bin mapping compensation for tilt is active, this is then a vertical range to the bin centres, see adcp.processingComments to see if bin mapping was applied. (Prior to Feb 26, 2015: vector of distance to start of each bin)
  • cellDepth: vector, starting depth of each cell calculated from range and deployment depth (may be inaccurate if instrument is vertically mobile)
  • u,v,w: 2D matrices, East/North/Up velocities relative to True North, derived using raw velocity matrix, orientation, coordinate system, transformation matrix and one of a) calculated magnetic declination based on time and location (for mobile adcps) or b) meta.deviceHeading (fixed position ADCPs)
  • velocity: 3D matrix, corresponds directly to output of instrument and so depends on configuration coordinate system
  • amplitude: 3D matrix, amplitude time-series for each of the three receivers
  • correlation: 3D matrix, signal correlation coefficient time-series for each of the three receivers (only available for HR-Profilers)
  • compassHeading: vector, magnetic compass heading time-series
  • pitch: vector, pitch time-series
  • roll: vector, roll time-series
  • pressure: vector, pressure time-series
  • temperature: vector, temperature time-series
  • soundSpeed: vector, sound speed time-series (often constant, depending on configuration)
  • voltage: vector, battery voltage time-series
  • error: vector, error code

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

  • SN: instrument type and serial number
  • headSN: head serial number
  • boardFrequency: board frequency
  • headFrequency: head frequency
  • fwVersion: firmware version
  • hwRevision: hardware revision
  • PICversion: PIC code version
  • avgInterval: time the instrument is actively measuring within the profile interval
  • measurementInterval: time between each measurement (i.e., data output rate)
  • compassUpdateRate: rate at which compass readings are updated
  • nbeams: number of transducers/beams.
  • ncells: number of cells
  • npings: number of pings per profile
  • 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.
  • cellSize: size of each cell. See Nortek forum discussion for calculation details.
  • coordSys: coordinates system of raw data (BEAM, XYZ or ENU)
  • orientation: Up or Down indicates the direction transducers are facing
  • transformationMatrix: matrix, used to convert from beam to xyz coordinates
  • correlationThreshold: correlation threshold for resolving ambiguities
  • rawDataVelocityScaling: scale conversion from raw data to data in mat file - always converts all velocities to m/s, from either mm/s or 0.1 mm/s. (Nortek Software does this as well).

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

Example: NortekADCP1504_20101022T000021Z.mat

NETCDF

NetCDF is a machine-independent data format offered by numerous institutions, particularly within the earth and ocean science communities. Additional resources are noted here.

Example: NORTEKAQDPRO2958_20110904T000042Z.nc

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