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| Siegelman, Lia; Klein, Patrice; Thompson, Andrew F.; Torres, Hector S.; Menemenlis, Dimitris. |
| Recent studies demonstrate that energetic sub-mesoscale fronts (10–50 km width) extend in the ocean interior, driving large vertical velocities and associated fluxes. However, diagnosing the dynamics of these deep-reaching fronts from in situ observations remains challenging because of the lack of information on the 3-D structure of the horizontal velocity. Here, a realistic numerical simulation in the Antarctic Circumpolar Current (ACC) is used to study the dynamics of submesocale fronts in relation to velocity gradients, responsible for the formation of these fronts. Results highlight that the stirring properties of the flow at depth, which are related to the velocity gradients, can be inferred from finite-size Lyapunov exponent (FSLE) at the surface.... |
| Tipo: Text |
Palavras-chave: Altimetry; Finite-size Lyapunov exponent; Ocean dynamics; Sub-mesoscale. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00645/75666/76532.pdf |
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| Torres, Hector S.; Klein, Patrice; Menemenlis, Dimitris; Qiu, Bo; Su, Zhan; Wang, Jinbo; Chen, Shuiming; Fu, Lee-lueng. |
| Internal gravity waves (IGWs) and balanced motions (BMs) with scales < 100‐km capture most of the vertical velocity field in the upper ocean. They have, however, different impacts on the ocean energy budget, which explains the need to partition motions into BMs and IGWs. One way is to exploit the synergy of using different satellite observations, the only observations with global coverage and a reasonable spatial and temporal resolution. But we need first to characterize and understand their signatures on the different surface oceanic fields. This study addresses this issue by using an ocean global numerical simulation with high‐resolution (1/48o). Our methodology is based on the analysis of the 12,000 frequency‐wavenumber spectra to discriminate these... |
| Tipo: Text |
Palavras-chave: Oceanic surface motions; Satellite observations; Balanced motions; Internal gravity waves. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00464/57568/59746.pdf |
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| Siegelman, Lia; Klein, Patrice; Rivière, Pascal; Thompson, Andrew F.; Torres, Hector S.; Flexas, Mar; Menemenlis, Dimitris. |
| The ocean is the largest solar energy collector on Earth. The amount of heat it can store is modulated by its complex circulation, which spans a broad range of spatial scales, from metres to thousands of kilometres. In the classical paradigm, fine oceanic scales, less than 20 km in size, are thought to drive a significant downward heat transport from the surface to the ocean interior, which increases oceanic heat uptake. Here we use a combination of satellite and in situ observations in the Antarctic Circumpolar Current to diagnose oceanic vertical heat transport. The results explicitly demonstrate how deep-reaching submesoscale fronts, with a size smaller than 20 km, are generated by mesoscale eddies of size 50–300 km. In contrast to the classical... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00594/70562/71323.pdf |
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| Flexas, M. Mar; Thompson, Andrew F.; Torres, Hector S.; Klein, Patrice; Farrar, J. Thomas; Zhang, Hong; Menemenlis, Dimitris. |
| Estimates of the kinetic energy transfer from the wind to the ocean are often limited by the spatial and temporal resolution of surface currents and surface winds. Here, we examine the wind work in a pair of global, very high‐resolution (1/48° and 1/24° ), MITgcm simulations in Latitude‐Longitude‐Cap configuration (LLC) that provide hourly output at spatial resolutions of a few kilometers and include tidal forcing. A cospectrum analysis of wind stress and ocean surface currents shows positive contribution at large scales (>300 km) and near‐inertial frequency, and negative contribution from mesoscales, tidal frequencies and internal gravity waves (IGWs). Larger surface kinetic energy fluxes are in the Kuroshio in winter at large scales (40 mW m−2) and... |
| Tipo: Text |
Palavras-chave: Surface fluxes; Inertial oscillations; Wind power; Kinetic energy budget; Global ocean model; MITgcm. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00509/62058/66232.pdf |
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| Nakayama, Yoshihiro; Manucharyan, Georgy; Zhang, Hong; Dutrieux, Pierre; Torres, Hector S.; Klein, Patrice; Seroussi, Helene; Schodlok, Michael; Rignot, Eric; Menemenlis, Dimitris. |
| In the Amundsen Sea, modified Circumpolar Deep Water (mCDW) intrudes into ice shelf cavities, causing high ice shelf melting near the ice sheet grounding lines, accelerating ice flow, and controlling the pace of future Antarctic contributions to global sea level. The pathways of mCDW towards grounding lines are crucial as they directly control the heat reaching the ice. A realistic representation of mCDW circulation, however, remains challenging due to the sparsity of in-situ observations and the difficulty of ocean models to reproduce the available observations. In this study, we use an unprecedentedly high-resolution (200 m horizontal and 10 m vertical grid spacing) ocean model that resolves shelf-sea and sub-ice-shelf environments in qualitative... |
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| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00593/70560/68742.pdf |
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