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Existing implementations

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Existing implementations#

At present we are aware of only two implementations of echosounder data processing levels, one from the Australian Integrated Marine Observing System (IMOS) [Haris et al., 2021, Haris et al., 2018] and the other from the Atlantic Deepwater Ecosystem Observatory Network (ADEON) [Heaney et al., 2020].

IMOS#

The IMOS SOOP-BA NetCDF convention (Ships Of OPportunity Bio-Acoustic [Haris et al., 2021, Haris et al., 2018]) uses the broader IMOS “file_version” processing level categorization for marine data. The categorizations includes:

  • L0: raw data

  • L1: quality controlled data

  • L2: derived data products

The IMOS SOOP-BA data are stored in a NetCDF format that is metadata-rich and follows broad ocean and earth science data and metadata standards. The data products include many variables, such as uncorrected and unfiltered Sv, processed Sv (motion correction and a series of noise filtering), metrics derived from Sv, and ancillary oceanographic data. Unmodified raw data files are archived and made available only upon request (Haris, K., pers. comm.).

ADEON#

ADEON developed a set of six processing levels (L0-L5) for passive and active acoustics [Heaney et al., 2020]:

  • L0: raw, unprocessed data files generated by instruments

  • L1: calibrated time series data, including calibrated volume backscattering strength (Sv)

  • L2: the first level of data processed from the calibrated data, such as depth-integrated Sv with noise removal applied

  • L3-L5: higher-order processing, including signal classifications, interpolated products and synthesis or modeled products.

The ADEON specification contains a table that compares the ADEON levels with those from NASA EOS and the French IFREMER program [IFREMER, 2019]. In practice, the ADEON focus for active acoustics was largely on L0-L2. Widely used data formats such as CSV are used for the resulting products.

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