Benoit Legresy (CSIRO, Australia); Jack Beardsley (Integrated Marine Observing System, Australia); Matt King (University of Tasmania, Australia)

The Bass Strait altimeter validation facility (40° 39’S, 145° 36’ E) has contributed cycle-by-cycle estimates of absolute altimeter bias for over 25 years. The primary comparison point is located on the Jason-series reference orbit – the facility itself couples moored oceanographic sensors, episodically deployed GNSS equipped buoys, a coastal tide gauge and continuously operating GNSS reference stations to derive absolute altimeter bias. Additional instrumentation is located at comparisons points positioned at cross overs for the Sentinel-3A and Sentinel-3B missions, respectively.

Here we present our updated results from the Bass Strait site. We detail the evolution of absolute bias from the Jason-3 and Sentinel-3A missions. We discuss developments in processing GPS buoy data with a focus towards estimating sea surface slope over short (< 1km) and medium (~8 km) separation distances to emphasize the potential use of GNSS equipped buoys for the validation of future swath based altimeter data using a purely geometric approach.