Hydrophone Array Raw Data
The raw data format for the Institute for Ocean Sciences (IOS) hydrophone arrays is a binary hyd file. These arrays consistent of three hydrophones, a mounting frame and a data acquisition system. The system collects acoustic data and stores it in 5 minute segments in three separate channels within a single hyd file. MATLAB code was provided by the Instrument Development Group at IOS to read these files. Once read, we produce the standard suite of hydrophone data products (audio data and hydrophone spectral data). For additional information, see the instrument documentation under hydrophones, specifically, devices 22 and 1007, are active on the VENUS network and regularly produce hyd files. As this is a completely custom binary file, only expert users who have access to the aforementioned MATLAB code should download this data (contact us for more information about working with hyd files). The standard hydrophone data products, including wav, MP3 and spectrogram images, are suited for general use.
Oceans 2.0 API filter: dataProductCode=HARD
Revision History
- 20140123: initially made available in data search. This product has been available through VENUS data download since ~2009.
Data Product Options
Hydrophone Channel
H1
This option will cause the search to return results for hydrophone channel H1 only. The hydrophone arrays consist of multiple hydrophones connected to a single data acquisition computer, which collects the data into single files that have multiple channels (nominally raw hydrophone array files, although other formats can handle multiple channels). Data products may be produced from these files on a per channel basis and returned as specified.
This is the default option.
Oceans 3.0 API filter: dpo_hydrophoneChannel=H1
File-name mode field
'H1' is added to the file-name when the hydrophone channel option is set to H1, i.e. IOS3HYDARR02_20111211T152404.000Z-spect-H1.pdf.
H2
This option will cause the search to return results for hydrophone channel H2 only.
Oceans 3.0 API filter: dpo_hydrophoneChannel=H2
File-name mode field
'H2' is added to the file-name when the hydrophone channel option is set to H2, i.e. IOS3HYDARR02_20111211T152404.000Z-spect-H2.png.
H3
This option will cause the search to return results for hydrophone channel H3 only.
Oceans 3.0 API filter: dpo_hydrophoneChannel=H3
File-name mode field
'H2' is added to the file-name when the hydrophone channel option is set to H3, i.e. IOS3HYDARR02_20120801T090939.000Z-H3.mp3.
All
This option will cause the search to return results for all available hydrophone channels.
Oceans 3.0 API filter: dpo_hydrophoneChannel=All
File-name mode field
'H1', 'H2', 'H3', etc are added to the file-name.
Hydrophone Data Diversion Mode
Diversion Mode
For security reasons, the military occasionally diverts seismic and acoustic data. Over time how this diversion is performed has changed. Currently, when diverted the entire data set is removed. Diverted data is then reviewed by military authorities, if it does not contain sensitive recordings it is returned to the ONC archive.
Standard practice prior to August 2016: instead of diverting the entire data stream, the military diverted only a low frequency band of the data. When this filtering occurred, the remaining data's file-name was appended with 'HPF' for high-pass filtering, while the low-pass data was held for review. Usually that withheld/diverted data was returned, after a delay of 3 days to 2 months; those files are appended with 'LPF' for low-pass filtered. To further confuse matters, sometimes the file-name appending was not complete - half of the data stream was not appended with the LPF or HPF moniker (usually the HPF side), however, our data product software now detects this via time overlaps and handles the other half of the LPF/HPF even if it isn't named so. After 2016, diversions tended to be all or nothing and no low-pass diversion occurred. Recently, the LPF/HPF data splitting has occurred again.
Data diversion is further explained in the data diversion page. Feel free to contact us for support.
Original Data
This option will cause the search to return results for original data only. Files labelled with "-HPF" or "-LPF" are excluded as well as any files that overlap in time with "-HPF" or "-LPF" files. For spectral probability density plots and spectrograms, 'Data Diversion Mode: Original Data' will appear in the plot title.
This is the default option.
Oceans 3.0 API filter: dpo_hydrophoneDataDiversionMode=OD
Low Pass Filtered
Applies to pre-August 2016 data (with some exceptions). This option will cause the search to return results for diverted data that has been low pass filtered only (only files with "-LPF" in the their file-names). For spectral probability density plots and spectrograms, 'Data Diversion Mode: Low Pass Filtered' will appear in the plot title.
Oceans 3.0 API filter: dpo_hydrophoneDataDiversionMode=LPF
High Pass Filtered
Applies to pre-August 2016 data (with some exceptions). This option will cause the search to return results for diverted data that has been high pass filtered only (only files with "-HPF" in the their file-names). For spectral probability density plots and spectrograms, 'Data Diversion Mode: High Pass Filtered' will appear in the plot title.
Oceans 3.0 API filter: dpo_hydrophoneDataDiversionMode=HPF
All
This option will cause the search to return results for all data. For spectral probability density plots and spectrograms, 'Data Diversion Mode: High Pass Filtered' will appear in the plot title. This is only way to see data that overlaps in time with files labelled "-LPF" or "-HPF".
Oceans 3.0 API filter: dpo_hydrophoneDataDiversionMode=All
File-name mode field
"-LPF" or "-HPF" is added to the file-name when the quality option is set to high or low pass filtered data, i.e. ICLISTENHF1234_20110101T000000Z-HPF.wav. For spectral probability density data products, 'All' may be added to the file-name, as these plots can join LPF, Original and HPF data together into one plot if the spectral frequency bins are the same (data with different frequency content will make addition plots with labels indicating the frequency range). For brevity, 'Original' does not get added to the file-name.
Acquisition Mode
For hydrophones operating with a duty cycle that includes high and low frequency sample rates (the hydrophones alternate between low and high sample rates periodically, to save battery and memory storage in autonomous deployments). The low sample frequency data will likely have a sample frequency of 16 kHz and the high sample frequency data will likely have a sample frequency greater or equal to then 128 kHz.
Low Sample Frequency
This option will cause the search to return results for the low sample frequency data only (files with "-16KHZ" in their file-names). For spectral probability density plots and spectrograms, "Data Acquisition Mode: Low Frequency" will appear in the plot title.
Oceans 3.0 API filter: dpo_hydrophoneAcquisitionMode=LF
High Sample Frequency
This option will cause the search to return results for the high sample frequency data only (files with "-128KHZ" or similar in their file-names). For spectral probability density plots and spectrograms, "Data Acquisition Mode: High Frequency" will appear in the plot title.
Oceans 3.0 API filter: dpo_hydrophoneAcquisitionMode=HF
All
This option will cause the search to return results for both the low and high sample frequency data or other mode data. For spectral probability density plots and MAT files, the low and high frequency data will be segregated regardless of option.
Oceans 3.0 API filter: dpo_hydrophoneAcquisitionMode=All
File-name mode field
The sample frequency is added to the file-name for each data acquisition mode option, i.e. ICLISTENHF1234_20110101T000000Z-16KHZ.wav. The Spectrogram_ModeDurationDPO device attribute is populated on devices with a duty cycle, it is used to link the low frequency (LF) and high frequency (HF) acquisition modes with the exact file-name mode modifier string - if this link is not correct, the data acquisition mode option will not properly filter the data products.
Formats
hyd files are a unique binary format, readable by custom software only. These files are essentially containers for multiple wav files stuck together with a binary file header, in a single file. MATLAB code to read these files is available: readhydfile.m and associated functions. Please contact us for details.
Oceans 2.0 API filter: extension=hyd
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