CoAuthors

Benoit Legresy (CSIRO, Australia); Jack Beardsley (University of Tasmania, Australia); Boye Zhou (University of Tasmania, Australia); Matt King (University of Tasmania, Australia)

The Bass Strait altimeter validation facility (40° 39’S, 145° 36’ E) provides cycle-by-cycle estimates of absolute altimeter bias for the Jason-series, Sentinel-3A and Sentinel-3B missions. The facility uses an integrated geometric approach involving a suite of in situ sensors including moored oceanographic sensors, episodically deployed GNSS equipped buoys, a coastal tide gauge and continuously operating GNSS reference stations.

In preparation for fully SAR capable altimetry (Sentinel-6) and subsequently, swath-based interferometric altimetry (SWOT), several enhancements to the Bass Strait facility have been investigated. We detail our ongoing use of 5-beam ADCP instruments for the determination of shallow water SSH, current and wave field information using a pressure inverted echo sounder concept (PIES). Second, we review our progress in understanding small but significant systematic errors in SSH derived from GNSS equipped buoys. Together, advances in our in situ instrumentation seek to address an improved determination of along-track SSH (and SSH gradient) for the benefit of validating the next generation of altimeter missions. We present results from these investigations together with latest absolute bias results from the Bass Strait comparison points.