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The data is subject to diversion and filtering by the military, as described here. LPF/HPF data is normally fairly obvious as there will be a dramatic cut-off at either the high or low end of the frequencies and the filtered data that is shown will all appear at less than 40 dB. Data product options alter the results as well, see the data product options described below. If a diversion returns 'LPF' or 'HPF' filtered data and the user selects the 'All' data product option, and if the spectral frequencies available do not change, then LPF/HPF and original spectral data maybe combined in the same plot, where one would see the normal (as above) and some data at a much lower PSD. If LPF/HPF or any data has a different number of spectral frequencies, then the plots will break and won't be combined.
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Data availability may be limited for low-bandwidth deployments (Cambridge Bay). This data product is produced from hydrophone spectral MAT files, which are pre-processed and stored for fast retrieval. Spectral probability density plots are quick to generate if all the MAT files are pre-processed (~1 minute per week), if not, the spectral data has to be generated on the fly, which could take as long 1/2 day per one week plot. For advanced users, the data that forms the plots, the spectral probability density histogram, the percentiles and linear mean sound pressure level are also available in a MAT file product; please note that this MAT file product is distinct from hydrophone spectral MAT files.
Oceans 2.0 API filter: dataProductCode=HSPD
Revision History
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Hydrophone spectral probability density data products are available in PNG, PDF format for plots, and a MAT file product containing the data used in the plots: the spectral probability density histogram, percentiles and linear mean sound pressure level.
Oceans 2.0 API filter: extension={png,pdf,mat}
MAT (Hydrophone Spectral Probability Density)
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