Seminar: Observability of surface oceanic turbulence by the SWOT mission: filtering and characterization of errors for data inversion

  • Speaker: Laura Gómez Navarro, PhD student, Université Grenoble Alpes (France) and IMEDEA (Spain)







Esporles, January 24, 2019. 


The Surface Water Ocean Topography satellite is planned to be launched in 2021. For oceanographic purposes, it will provide an unprecedented dataset as in addition to the conventional 1D along track nadir data, it will also provide Sea Surface Height (SSH) data at a 15 km resolution (structures of 7.5 km in diameter) thanks to two 50 km wide swaths at each side of the nadir.



This will allow us to improve our knowledge of fine scale oceanic structures and to derive vertical velocities, which has a wide range of implications in physical and biogeochemical ocean interactions.  In order to do so, we need first to solve the challenges this new dataset presents: a new geometry of SSH data field, high spatial sampling but low temporal sampling and high satellite instrumental and geophysical errors. 



During my PhD project, we have focused mainly on the latter issue. Using high resolution Ocean General Circulation Models (OGCMs) and the SWOT simulator for Ocean Science tool, we simulated pseudo-SWOT data in the western Mediterranean. 



In a first study, we found that with a Laplacian diffusion filter we manage to resolve spatial wavelengths of 40-60 km (structures of 20-30 km in diameter) in this region, which represents a significant improvement in comparison with the present resolution of 150-200 km wavelengths. 



During the second part of the study, we use a derivatives penalization technique for filtering the SWOT noise, and it is shown that (1) the recovered spatial resolution is improved, and (2) the intensity of SSH signal is better preserved.



This innovative denoising method is a contribution to improve the capabilities to observe finescale oceanic structures and processes with the future SWOT data.





Date and Time: Tuesday, February 5, 12:00-13:00h

Place: IMEDEA Seminar Room