Simultaneous estimation of Ocean mesoscale and coherent internal tide Sea Surface Height signatures from the global Altimetry record

Ubelmann, Clément; Carrère, Loren; Durand, Chloé; Dibarboure, Gérald; Faugère, Yannice; Ballarotta, Maxime; Briol, Frederic; Lyard, Florent

doi:10.5194/os-2021-80

Cited by 6 publications

(9 citation statements)

References 15 publications

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“…Data availability. The internal tide solution from the MIOST analysis described in this article is available at https://doi.org/10.24400/527896/a01-2022.003 (Ubelmann et al, 2022) including a full description on how to use the data, in particular on how to reconstruct the internal tide solution from frequency to temporal space.…”

Section: Discussionmentioning

confidence: 99%

Simultaneous estimation of ocean mesoscale and coherent internal tide sea surface height signatures from the global altimetry record

Ubelmann¹,

Carrère

Durand

et al. 2022

Ocean Sci.

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Abstract. This study proposes an approach to estimate the ocean sea surface height signature of coherent internal tides from a 25-year along-track altimetry record, with a single inversion over time, resolving both internal tide contributions and mesoscale eddy variability. The inversion is performed on a reduced-order basis of topography and practically achieved with a conjugate gradient. The particularity of this approach is to mitigate the potential aliasing effects between mesoscales and internal tide estimation from the uneven altimetry sampling (observing the sum of these components) by accounting for their statistics simultaneously, while other methods generally use a prior mesoscale. The four major tidal components are considered (M2, K1, S2, O1) over the period 1992–2017 on a global configuration. From the solution, we use altimetry data after 2017 for independent validation in order to evaluate the performance of the simultaneous inversion and compare it with an existing model.

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Section: Discussionmentioning

confidence: 99%

Simultaneous estimation of ocean mesoscale and coherent internal tide sea surface height signatures from the global altimetry record

Ubelmann¹,

Carrère

Durand

et al. 2022

Ocean Sci.

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“…In addition, the growing needs to develop observing systems or methods with finer spatial scales and higher frequencies have been identified by the ocean scientific community and the Copernicus Services as research and development priorities to serve Copernicus marine users and decision-makers (see, for example, International Altimetry Team, 2021, or the "Copernicus Marine Service Evolution Strategy: R&D priorities -Version 5 June 30, 2021" document, https://marine.copernicus.eu/sites/default/files/media/ pdf/2021-09/CMEMSService_evolution_strategy_RD_ priorities_v5-June-2021.pdf, last access: 1 December 2022). Therefore, with the support of the French Space Agency (CNES), the development of new experimental products has been undertaken, aiming at improving the resolution of the current Level-3 and Level-4 sea-level products (Mulet et al, 2021a;Ballarotta et al, 2020;Ubelmann et al, 2022;Prandi et al, 2021) and preparing operational systems for the SWOT era (Ubelmann et al, 2015(Ubelmann et al, , 2021Le Guillou et al, 2021;Beauchamp et al, 2020).…”

Section: Introductionmentioning

confidence: 99%

Improved global sea surface height and current maps from remote sensing and in situ observations

Ballarotta

Ubelmann²,

Veillard³

et al. 2023

Earth Syst. Sci. Data

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Abstract. We present a new gridded sea surface height and current dataset produced by combining observations from nadir altimeters and drifting buoys. This product is based on a multiscale and multivariate mapping approach that offers the possibility to improve the physical content of gridded products by combining the data from various platforms and resolving a broader spectrum of ocean surface dynamic than in the current operational mapping system. The dataset covers the entire global ocean and spans from 1 July 2016 to 30 June 2020. The multiscale approach decomposes the observed signal into different physical contributions. In the present study, we simultaneously estimate the mesoscale ocean circulations as well as part of the equatorial wave dynamics (e.g. tropical instability and Poincaré waves). The multivariate approach is able to exploit the geostrophic signature resulting from the synergy of altimetry and drifter observations. Sea-level observations in Arctic leads are also used in the merging to improve the surface circulation in this poorly mapped region. A quality assessment of this new product is proposed with regard to an operational product distributed in the Copernicus Marine Service. We show that the multiscale and multivariate mapping approach offers promising perspectives for reconstructing the ocean surface circulation: observations of leads contribute to improvement of the coverage in delivering gap-free maps in the Arctic and observations of drifters help to refine the mapping in regions of intense dynamics where the temporal sampling must be accurate enough to properly map the rapid mesoscale dynamics. Overall, the geostrophic circulation is better mapped in the new product, with mapping errors significantly reduced in regions of high variability and in the equatorial band. The resolved scales of this new product are therefore between 5 % and 10 % finer than the Copernicus product (https://doi.org/10.48670/moi-00148, Pujol et al., 2022b).

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“…Since a large portion of barotropic to baroclinic energy transfer can be explicitly resolved in EXP2, we disable the parameterized topography drag which has been used in the barotropic model. Figure8compares the global internal tide fields of satellite based data MOIST (Multivariate Inversion of Ocean Surface Topography)(Ubelmann et al, 2021) and model simulations.We apply the radial filter with the radius of 4 o as high-pass filter to remove the barotropic tide signals in the open ocean in the model SSH output. After that, harmonic analysis of 1-year high-passed SSH time series is performed to obtain the simulated M2 internal tide amplitude.…”

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confidence: 99%

The development and validation of a global 1/32° surface wave-tide-circulation coupled ocean model: FIO-COM32

Xiao

Qiao

Shu

et al. 2022

Preprint

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Abstract. Model resolution and the included physical processes are two of the most important factors that determine the realism of the ocean model simulations. In this study, a new global surface wave-tide-circulation coupled ocean model FIO- COM32 with resolution of 1/32° × 1/32° is developed and validated. Promotion of the horizontal resolution from 1/10° to 1/32° leads to significant improvements of the simulations of surface eddy kinetic energy (EKE), fine structures of sub- mesoscale to mesoscale movements and the accuracy of simulated global tide. The non-breaking surface wave-induced mixing (Bv) is proved to be an important contributor that improves the agreement of the simulated summer mixed layer depth (MLD) of the model and the Argo observations even with high horizontal resolution of 1/32°, the mean error of the simulated mid-latitude summer MLD is reduced from -4.8 m in numerical experiment without Bv to -0.6 m in experiment with Bv. With the global tide is included, the global distributions of internal tide can be explicitly simulated in this new model and is comparable to the satellite observations. Comparisons using Jason3 along-track sea surface height (SSH) wave-number spectral slopes of mesoscale ranges show that internal tide induced SSH undulations is a key factor contributing to the substantially improved agreement of model and satellite observations in the low latitude and low EKE regions. For ocean model community, surface wave, tidal current and ocean circulation have been separating into different streams for more than half century. It should be the time to merge these streams for new generation ocean model development.

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Simultaneous estimation of Ocean mesoscale and coherent internal tide Sea Surface Height signatures from the global Altimetry record

Cited by 6 publications

References 15 publications

Simultaneous estimation of ocean mesoscale and coherent internal tide sea surface height signatures from the global altimetry record

Simultaneous estimation of ocean mesoscale and coherent internal tide sea surface height signatures from the global altimetry record

Improved global sea surface height and current maps from remote sensing and in situ observations

The development and validation of a global 1/32° surface wave-tide-circulation coupled ocean model: FIO-COM32

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