Data-driven and learning-based interpolations of along-track Nadir and wide-swath SWOT altimetry observations

Maxime Beauchamp (1, 2) , Ronan Fablet (1, 2) , Clément Ubelmann (3) , Maxime Ballarotta (4) , Bertrand Chapron (5)

1 IMT Atlantique - SC - Département Signal et Communications
2 Lab-STICC_IMTA_CID_TOMS
3 Ocean Next
4 CLS - Collecte Localisation Satellites
5 IFREMER - Institut Français de Recherche pour l'Exploitation de la Mer

Over the last years, a very active field of research aims at exploring new data-driven and learning-based methodologies to propose computationally efficient strategies able to benefit from the large amount of observational remote sensing and numerical simulations for the reconstruction, interpolation and prediction of high-resolution derived products of geophysical fields. In this paper, we investigate how they might help to solve for the oversmoothing of the state-of-the-art optimal interpolation (OI) techniques in the reconstruction of sea surface height (SSH) spatio-temporal fields. We focus on a small region, part of the GULFSTREAM and mainly driven by energetic mesoscale dynamics. Based on an Observation System Simulation Experiment (OSSE), we will use the the NATL60 high resolution deterministic ocean simulation of the North Atlantic to generate two types of pseudo altimetric observational dataset: along-track nadir data for the current capabilities of the observation system and wide-swath SWOT data in the context of the upcoming SWOT mission. We briefly introduce the analog data assimilation (AnDA), an up-to-date version of the DINEOF algorithm, and a new NN-based end-to-end learning framework for the representation of spatio-temporal irregulary-sampled data. We evaluate how some of these methods are a significant improvements, particularly by catching up the small scales ranging up to 30-40km, inaccessible by the conventional methods so far. A clear gain is also demonstrated when assimilating jointly wide-swath SWOT and (agreggated) along-track nadir observations.

Domaines: Océan, Atmosphère; Machine Learning [stat.ML]

Maxime Beauchamp, Ronan Fablet, Clément Ubelmann, Maxime Ballarotta, Bertrand Chapron. Data-driven and learning-based interpolations of along-track Nadir and wide-swath SWOT altimetry observations. CI 2020 : 10th International Conference on Climate Informatics, Sep 2020, Oxford, United Kingdom. ⟨10.1145/3429309.3429313⟩. ⟨hal-02929973⟩