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ASL AWCP Time Series

Data files for ASL Science Environmental's Acoustic Water Column Profilers (AWCPs) are described here. Ancillary data (e.g., temperature, pitch, roll) are also available independently.

Revision History

  1. 20110302: Beta MAT product released

Formats

This data is available in MAT format. Content descriptions and example files are provided below. A new file is started at the start of each day or when the driver is restarted (this should account for configuration changes, site changes, etc).

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: 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 (if NaN, heading is not fixed).
  • 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.
  • searchID: Identifier for search request.
  • dataProductVer: Version of data product.

data: structure containing the AWCP 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 start of each bin
  • profileData: 2D matrix, raw amplitude time-series for receiver
  • temperature: vector, temperature time-series
  • tiltX: vector, tilt X-direction time-series
  • tiltY: vector, tilt Y-direction time-series
  • voltage: vector, battery voltage time-series
  • timeInstrumentClock: vector, instrument clock time-series
  • nProfile: vector, profile number
  • error: vector, error code
  • pingAquired: vector, number of pings acquired for profile
  • pingFirst: vector, index of first ping acquired in profile
  • pingLast: vector, index of last ping acquired in profile
  • profileStatus: vector, profile status code
  • sensorStatus: vector, sensor status code

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

  • profileInterval: number of seconds per profile
  • digitizationRate: rate at which received signal is digitized
  • soundSpeed: sound speed used for calculation of range
  • lockoutSamples: number of samples to ignore
  • lockoutDistance: blanking distance (based on number of lockout samples)
  • nBins: number of bins in profile
  • nSamplesPerBin: number of samples used to calculate amplitude in each bin
  • nSamples: number of samples in profile
  • rangeMaximum: maximum range from which samples are digitized
  • nPings: number of pings to average for profile
  • pingPeriod: number of seconds between pings
  • storeSTD: determines whether to store enough information to compute the standard deviation of each profile
  • phase: phase used to acquire profile
  • nChannels: number of channels (in case instrument is capable of having multiple frequencies)
  • gain: gain setting
  • pulseLength: pulse length
  • boardNumber: board number
  • frequency: frequency of echosounder

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

Example: ASL_AWCP5_WCP16_20100915T165700Z.mat

Example Plotting Matlab Code

%% load a .mat file from the ASL AWCP
uiload

%% do some plots
figure
map=jet;
map = \[\[1 1 1\]; map\]; % Fade to black at the end of the spectrum (when log10 values are \~=0 they will appear as black)
colormap(jet);
imagesc(data.time, data.range, 20*log10(data.profileData)')
colorbar
axis xy
datetick
ylabel('Range (m)')
xlabel('Time (UTC)')
title('ASL AWCP')
print awcp1.png \-dpng \-r300

figure
subplot(3,1,1)
title('ASL AWCP Ancillary Data')
plot(data.time, data.temperature)
ylabel('Temperature (C)')
datetick
grid on
box on
subplot(3,1,2)
plot(data.time, data.tiltX)
ylabel('Tilt X (degrees)')
datetick
grid on
box on
subplot(3,1,3)
plot(data.time, data.tiltY)
ylabel('Tilt Y (degrees)')
xlabel('UTC Time')
datetick
grid on
box on
print awcp2.png \-dpng \-r300

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