Data Prep and Quality Check

Data Prep

Offloading and Decompressing SUD files

After each drifting buoy deployment, SUD files (compressed audio file with recording metadata) were offloaded from each recording device. The SUD files were extracted using SoundTrap Host software file extraction tool. The exported files include raw audio files (.wav), recording logs, and accelerometer data.

Decimation and LTSAs

To prep for analysis, the data were decimated and Long Term Spectral Averages (LTSA) were created. Data were decimated to 48 kHz, 12 kHz, and 500 Hz using the MATLAB based Triton Software Package. LTSAs were also made for each dataset with the following parameters;

• 384 kHz (raw data): 5 seconds, 200 Hz

• 48 kHz: 5 seconds, 1 Hz

• 12 kHz: 5 seconds, 1 Hz

• 500 Hz: 1 seconds, 1 Hz

The data start and end times were also determined from the full bandwidth LTSAs and the data was truncated before analysis.

QAQC

The full bandwidth LTSAs were used to assess the overall data quality as good, compromised, or unusable.

A recording QAQC was also run to identify abnormal file sizes, gaps in the recordings, or other recording abnormalities. This QAQC was ran using a custom MATLAB script (PAMmisc QAQC R version).

Noise Assessment

Using the Triton Logger remora, the 384 kHz LTSAs were manually scanned to log time periods with noisy or compromised data, which would be excluded from analysis.