An Integrated Hydrophone Calibration System for Ocean Observing: ONC HydroCal

In this paper, we present a hydrophone calibration system and its integration within an ocean observatory network to provide near-live calibrated hydrophone data. Ocean Networks Canada (ONC), an initiative of the University of Victoria, operates world-leading ocean observatories on Canada's three coasts. ONC's data infrastructure, collectively known as Oceans 3.0, archives and serves data collected from many devices, particularly hydrophones. Calibrated passive acoustic data facilitates significant research, however, gathering and maintaining hydrophone calibration and data quality is a process under ongoing improvement. ONC has developed a hydrophone calibration system, known as ONC HydroCal, to provide calibrations as part of ONC's regular maintenance cycle. Recent improvements include integrating ONC HydroCal calibration into Oceans 3.0, where the calibration is used in a variety of data products.