Day 4

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Paper title Up to date ocean surface wave information around Australia
Authors
  1. Salman Saeed Khan Commonwealth Scientific and Industrial Research Organisation (CSIRO)
  2. Mark Hemer Commonwealth Scientific and Industrial Research Organisation (CSIRO)
  3. Ali Tamizi Commonwealth Scientific and Industrial Research Organisation (CSIRO)
  4. Ian Young University of Melbourne Speaker
  5. Diana Greenslade Australian Bureau of Meteorology
Form of presentation Poster
Topics
  • A8. Ocean
    • A8.14 Remote-sensing of Ocean Waves and their Applications
Abstract text IMOS (Integrated Marine Observing System) OceanCurrent (oceancurrent.imos.org.au) is a marine data visualisation digital resource that helps communicate and explain up to date ocean information around Australia. The information offers benefit to a broad range of users including swimmers, surfers, recreational fishers, sailors, and researchers using data collected from satellites, instruments deployed in the ocean, and accessible model outputs. The platform includes near-real-time data for sea surface temperature, ocean colour, and sea level anomaly from various satellite missions and in-situ instruments such as Argo, current meters, gliders, and CTDs etc. Until now, ocean surface wave information, both from in-situ wave rider buoys and satellite missions, has not been captured in OceanCurrent.

Australia has a growing network of moored coastal wave rider buoys. Network gaps are being identified (Greenslade et al., 2018, 2021) and filled, and new low-cost wave buoys are also being tested and deployed alongside traditional systems, further increasing the in-situ surface wave data captured. The publicly available national wave data network consists of approximately 35+ platforms operated by several different State and Commonwealth agencies and industry-contributed data (Greenslade et al., 2021). As it can be challenging and time-consuming to gather wave observations from various sources for large scale national or regional studies, IMOS AODN (Australian Ocean Data Network) Portal has strived to build an archive (and a near real time feed) of available national wave buoy observations. The AODN service is also being expanded by adding more platforms and by improving the meta-data of buoy record. Historical and near-real-time national wave data from a substantial set of wave buoys can now be easily accessed.

International satellite remote sensing radar altimeter and synthetic aperture radar (SAR) missions are also providing open data of surface wave observations globally. Also, CFOSat SWIM instrument has been providing global surface wave spectra measurements since launch in 2018 (Hauser et al., 2021). Using these valuable resources, Australia has developed, and continues to maintain, long-term multi-mission databases of calibrated wave height observations from radar altimeters (Ribal et al., 2019) and long-wave spectra from selected SAR missions (Khan et al., 2021). Some of these databases are also providing near real time feeds that can be exploited to gather up to date wave information.

An experimental national ocean surface waves product is under development for IMOS OceanCurrent Portal by integrating surface waves information from coastal buoys and satellite missions. As both radar altimeter and SAR satellites are polar orbiting with relatively narrow swaths (~10-20 km) over open ocean, during any short time window at best there are only a few along-track satellite measurements available. To convey a full representation of the wave field, background wave information from Bureau of Meteorology’s (BoM) AUSWAVE initialisation time step (t0) is shown. Surface wave maps are created at 2-hourly time steps with t0 as the central time showing AUSWAVE significant wave height and peak wave direction. Coastal buoy observations including significant wave height, mean wave direction, mean wave period, and directional spread within t0 +/- 3 hours, radar altimeter significant wave height within t0 +/- 1 hour, and peak wave direction and mean period extracted from SAR spectra within t0 +/- 30 mins are displayed, when available. Monthly videos from 2-hourly surface wave maps are also created to have a synoptic record of wave field propagation from ocean to the coast. The surface wave map archive currently spans 2021 and is planned to contain up to date (up to a few hours delay) surface wave information.

Once available on OceanCurrent, the hope is that this product will enable the wider community of recreational marine users and researchers to extract relevant surface wave information as needed and provide direct societal benefits by providing a national view of easily available and integrated surface wave information.

A sample image of the surface waves product is attached with the abstract to help reviewers, but it will likely be unavailable for the online abstract version (if accepted) as advised by the symposium organisers.

References

Greenslade, D. J. M., Zanca, A., Zieger, S., and Hemer, M. (2018): Optimising the Australian wave observation network. J. South. Hemisphere Earth Syst. Sci., 68, 184–200, https://doi.org/10.22499/3.6801.010.

Greenslade, D. J. M., Hemer, M. A., Young, I. R. & Steinberg, C. R. (2021). Structured design of Australia’s in situ wave observing network, Journal of Operational Oceanography, doi: 10.1080/1755876X.2021.1928394

Ribal, A., Young, I.R. (2019). 33 years of globally calibrated wave height and wind speed data based on altimeter observations. Sci Data 6, 77. https://doi.org/10.1038/s41597-019-0083-9

Khan, S. S., Echevarria, E. R., & Hemer, M. A. (2021). Ocean swell comparisons between Sentinel-1 and WAVEWATCH III around Australia. J. Geophys. Res: Oceans, 126, e2020JC016265. https://doi.org/10.1029/2020JC016265

D. Hauser et al., (2021). New Observations from the SWIM Radar On-Board CFOSAT: Instrument Validation and Ocean Wave Measurement Assessment," in IEEE Transactions on Geoscience and Remote Sensing, vol. 59, no. 1, pp. 5-26, Jan. 2021, doi: 10.1109/TGRS.2020.2994372.