David Cotton

Dual beam along-track interferometic SAR to MAP total ocean surface current vectors with the airborne wavemill proof-of-concept instrument: Impact of wind-waves

Synoptic maps of total ocean surface currents from space are needed to improve the characterisation and parameterisations of oceanic sub-mesoscale dynamics and represent their impact on global ocean circulation, air-sea exchanges and the marine ecosystem. Wavemill is a satellite mission concept based on a dual beam along-track interferometric SAR principle. An airborne proof-of-concept campaign took place in the tidally-dominated Irish Sea in 2011. A comprehensive collection of airborne flights arranged in a star pattern permitted to sample various azimuthal directions. Here, it is shown that the impact of ocean waves on the measured ocean surface motion can be as large or even larger than the strong tidal current (0.7m/s). Using in situ validation measurements and airborne Wavemill data, the azimuth dependence and magnitude of this wind-wave velocity artefact is characterised.

EnviSat Altimeter system: Near Real Time long-term monitoring

ESA declared the end of the EnviSat mission on 9th May 2012, after 10 years of life (doubling the initial expected 5 years of operations). Monitoring of Near Real Time (NRT) data started in 2003 to assess the quality of measurement and calibration of the EnviSat Radar Altimeter instrument. Since then, NRT data has been stored to build a comprehensive database of altimeter parameters that can be now used not only to assess the instrument calibration and the processing data quality, but also as a starting point for defining specific performance objectives for NRT data for future altimeter missions.