Abstract's details

Coastal Processing from the Copernicus Altimeters: the CORS processor outcomes

Pablo Garcia (isardSAT, Spain)


Alba Granados (isardSAT, Spain); Mònica Roca (isardSAT, Spain); Segarra Federico (isardSAT, Spain)

Event: 2022 Ocean Surface Topography Science Team Meeting

Session: Coastal Altimetry

Presentation type: Type Poster

The Copernicus constellation has today 3 altimeters in flight, the two Sentinel-3, A & B, and the most recent altimetric mission Sentinel-6, as a continuation of a long historical series. All of them are operating the new standard Synthetic Aperture Radar mode, enabling for the first time an enhanced resolution sea surface monitoring over the global Ocean (CryoSat-2 was operating in SAR / SARin only over dedicated areas).
Coastal zones are crucial for the human development, and the characterisation of the ocean processes near to the coast is a must. The sea level rise is one of the most pressing climate change impacts, and although it is driven by global ocean forcing, refining this variable, along with sub-mesoscale ocean dynamics in the last 10 km to the coast, is still a challenge in the altimetry field.
Dedicated processing evolutions are needed for these areas when using altimetry data to derive the geophysical retrievals Sea Surface Height (SSH) and Significant Wave Height (SWH). The contribution of undesired targets is to be addressed and the retracking process is to be adapted. This has been the goal of this study, developed over the recent years, refining the processing steps of an algorithm that has been designed, implemented, and validated over a variety of complex coastal topography areas and different sea states.
The validation outcomes give a consistent SSH noise reduction of around 50% over different validation areas, such as the Mediterranean Sea. In the other hand, Power Spectral Density (PSD) studies show a better (denoised) SWH PSD over the full range of wavelengths from the largest (real geophysical signal) to the smallest scales (measurements noise). The SSH median bias between the ocean and coastal isardSAT retracking outputs is about 5 mm, while the SWH median bias is about 10 cm.
SAR mode data from the 3 Copernicus altimeters is used for this investigation. The coastal processing is focussed at filtering out as much as possible the sea surface signal contamination, with the minimum degradation of the sea surface scientific information. This specific processing comes from the idea explained at (Garcia et al.,2018, https://doi.org/10.1016/j.asr.2018.03.015) using CryoSat-2 SARin data, adapted to Copernicus altimeters SAR data.
isardSAT has developed this study as ESA Expert Support Laboratory within the Sentinel-3A Mission Performance Centre team and within the CORS (Coastal Ocean Retracking for Sentinels) project as contribution to the Sentinel-6 Validation Team.

Poster show times:

Room Start Date End Date
Mezzanine Tue, Nov 01 2022,17:15 Tue, Nov 01 2022,18:15
Mezzanine Thu, Nov 03 2022,14:00 Thu, Nov 03 2022,15:45
Pablo Garcia