A Deep Learning Approach to Extract Internal Tides Scattered by Geostrophic Turbulence
In: ISSN: 0094-8276, 2022
Online
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Zugriff:
International audience ; Since the launch of TOPEX/Poseidon, oceanographers have used the geostrophic assumption to infer sea surface velocity from Sea Surface Height (SSH). However, while an estimated 90% of the ocean's kinetic energy exists in the form of currents in quasigeostrophic balance (hereafter qualified as "balanced"; see Ferrari & Wunsch, 2009), one still must account for "unbalanced" flows such as internal tides, hereafter "ITs", for a refined inference of balanced currents (Fu & Ferrari, 2008). Furthermore, ITs play a crucial role in ocean mixing (Lien & Gregg, 2001; Whalen et al., 2020), and are helpful in detecting ocean temperature changes (Zhao, 2016). Therefore, whether ITs are considered "noise" (e.g., for inferring balanced flows) or "signal" (e.g., for inferring tidally induced mixing), their proper extraction from altimetry data is essential. For decades, IT extraction has been conducted via harmonic analysis (Munk & Hasselmann, 1964), a method that relies on a close phase relationship (or coherence) between ITs and astronomical forcings. Departures from this condition are sometimes referred to as "incoherence" (Ponte & Klein, 2015; Zaron & Rocha, 2018). Current altimetry has a typical spatial resolution of O(100) km (Ballarotta et al., 2019), which is sufficient to retrieve mode-1 and some of the mode-2 IT wavelengths of semidiurnal tides, along with the dominant turbulent balanced
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A Deep Learning Approach to Extract Internal Tides Scattered by Geostrophic Turbulence
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Autor/in / Beteiligte Person: | Wang, Han ; Grisouard, Nicolas ; Salehipour, Hesam ; Nuz, Alice ; Poon, Michael ; Ponte, Aurélien, L ; University of Toronto ; Research, Autodesk ; Laboratoire d'Océanographie Physique et Spatiale (LOPS) ; Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) ; Océan Dynamique Observations Analyse (ODYSSEY) ; Université de Bretagne Occidentale - UFR Sciences et Techniques (UBO UFR ST) ; Université de Brest (UBO)-Université de Brest (UBO)-Université de Rennes (UR)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Inria Rennes – Bretagne Atlantique ; Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-IMT Atlantique (IMT Atlantique) ; Institut Mines-Télécom Paris (IMT)-Institut Mines-Télécom Paris (IMT) |
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Zeitschrift: | ISSN: 0094-8276, 2022 |
Veröffentlichung: | HAL CCSD ; American Geophysical Union, 2022 |
Medientyp: | academicJournal |
DOI: | 10.1029/2022GL099400 |
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