Ocean Swell Comparisons Between Sentinel‐1 and WAVEWATCH III Around Australia

Abstract

AbstractAn intercomparison between directional wave spectra derived from Sentinel‐1 Synthetic Aperture Radar (SAR) satellites and a WAVEWATCH III model hindcast in the wider Australian region is presented. The coastal buoy network around Australia is considerably sparse, and only a handful of buoy measurements exist in deeper oceans. National and regional scale wave models require validation and verification through intercomparisons with available observations to be confidently adopted and improved. In the absence of dense in‐situ measurements, satellite‐derived surface wave data provide an invaluable and independent source of observations. Satellite altimeters provide well‐calibrated significant wave height data, but do not resolve wave directions, and are also not the platform of choice for resolving wave periods. SAR satellites that routinely map ocean surface waves fill this gap as they are able to measure directional wind‐wave spectra of long period waves. This constitutes an important satellite data stream for better understanding the propagation of swell waves across ocean basins, and for comparisons with national and down‐scaled wave models. However, both SAR wave measurements as well as wave models do not represent the truth and need qualification before regarding them as reliable data sets. The aim of this article is to perform an intercomparison of a wave model hindcast with SAR‐derived wave information in the wider Australian region. The comparisons are done in the context of mean wave climate and its seasonal variability, and demonstrate good agreement for wave heights and periods. Valuable insights into possible sources of disagreement are given.