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Projects

SWOT validation and interpretation from Bass Strait and surrounds

Principle Investigator: Christopher Watson (University of Tasmania​)

Co-Investigator(s): Benoit Legresy

Collaborator(s): Andrea Hay

This project seeks to further understand and interpret SWOT data in the vicinity of a series of key locations around Australia and the Southern Ocean. The work focuses on a novel and complimentary in situ data set collected from the Bass Strait altimeter validation facility located within the SWOT Fast Sampling Phase. Ongoing intercomparison with in situ data from this region provides direct connection to the heritage of nadir altimeter validation over 30+ years at the Bass Strait facility.

Bass Strait provides a well understood and flexible ocean validation target for SWOT located in the coastal domain (30-80 m depth). The data collected and under analysis from this site is highly complementary to other validation sites, offering the chance to investigate intra-swath variability in SSH, sea state and wet tropospheric delay in the near coast domain. Secondary targets at the SOFS location in the Southern Ocean and Davies Reef / Yongala in the Great Barrier Reef offer opportunity to explore SWOTs capability in very different environments.

The work presented here represents further development of a geometric geodetic approach to validation that includes in situ data from 9 Global Navigation Satellite System (GNSS) / Inertial Navigation System (INS) equipped buoys, an array of coastal oceanographic moorings (pressure, temperature, salinity and 5-beam ADCPs / current, wave, pressure inverted echo sounders - CWPIES), and regional high-resolution oceanographic and atmospheric modelling over the Bass Strait domain. The work includes analysis of concurrent Sentinel-6 Michael Freilich and Sentinel 3A/3B data. Our project will offer improved understanding of SWOT data in addition to a refined understanding of noise contributions from various in situ data types – this will be important in assessing possible validation approaches and error budgets associated with future swath missions.

Detailed view of the Bass Strait altimeter validation facility
Detailed view of the Bass Strait altimeter validation facility. Ground tracks for nadir missions: Jason-series (red), Sentinel-3A (cyan) and Sentinel-3B (blue) missions are shown as coloured lines. The SWOT 1-day repeat fast sampling orbit is shown in yellow. Various in situ data has been collected within the descending right (western) swath. The along track line of deployment instrumentation (including GNSS equipped buoys and sub-surface moored oceanographic instruments) follows the Jason-series / Sentinel-6 Michael Freilich ground track (red).