Improving Data Quality for the Australian High Frequency Ocean Radar Network through Real-Time and Delayed-Mode Quality-Control Procedures

Abstract

Quality-control procedures and their impact on data quality are described for the High-Frequency Ocean Radar (HFR) network in Australia, in particular for the commercial phased-array (WERA) HFR type. Threshold-based quality-control procedures were used to obtain radial velocity and signal-to-noise ratio (SNR), however, values were set through quantitative analyses with independent measurements available within the HFR coverage, when available, or from long-term data statistics. An artifact removal procedure was also applied to the spatial distribution of SNR for the first-order Bragg peaks, under the assumption the SNR is a valid proxy for radial velocity quality and that SNR decays with range from the receiver. The proposed iterative procedure was specially designed to remove anomalous observations associated with strong SNR peaks caused by the 50 Hz sources. The procedure iteratively fits a polynomial along the radial beam (1-D case) or a surface (2-D case) to the SNR associated with the radial velocity. Observations that exceed a detection threshold were then identified and flagged. After removing suspect data, new iterations were run with updated detection thresholds until no additional spikes were found or a maximum number of iterations was reached.

Interoperability of Direction-Finding and Beam-Forming High-Frequency Radar Systems: An Example from the Australian High-Frequency Ocean Radar Network

“…Results shown here refer to the radar grid point closest to the mooring locations. For WERA HFR systems, comparison metrics are in relatively good agreement with previously reported findings in different ocean regions (for instance [1,2]), but poorer compared to a previous validation in the same area for a different time period [34]. This is particularly true for FRE when compared to all the mooring data, with the exception of mooring WATR10.…”

“…The Australian Ocean Radar facility is part of the Integrated Marine Observing System (IMOS), a national collaborative research infrastructure tasked with collection and dissemination of ocean data [34]. The facility, based at the University of Western Australia, manages both direction-finding (SeaSonde) and phased-array (WERA) HFR systems.…”

“…Long-range (9.335 MHz) WERA HFR systems are also operational in the South Australian Gulf (SAG) regions. Additional details on operational settings, such as frequency band and bandwidth, accuracy levels, and quality-control (QC) procedures specific to the WERA HFR systems, and main limitations of the Australian HFR systems, including strong interference within the operating frequency bands, are provided in References [34,35].…”

Implementation of the Listen-Before-Talk Mode for SeaSonde High-Frequency Ocean Radars

“…Along the coasts of the US, for instance, more than 100 HFR systems are presently in operation, and the number of deployments steadily increases both in the Asia-Pacific regions and Europe. Extensive validation analyses and deployments in a variety of environments have also proven their general reliability [1][2][3][4].…”

“…Other HFR systems are also available, such as the PISCES or the University of Hawaii's HFRs. See, for instance, [1][2][3][4] and references herein for a more exhaustive literature review and for an assessment of their interoperability.…”