Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea
<p>An array of Lagrangian instruments (more than 100 drifters and a profiling float) were deployed for several days in the coastal waters of the southeastern Ligurian Sea to characterize the near-surface circulation at the submesoscale (<span class="inline-formula"><<...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2023-11-01
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| Series: | Ocean Science |
| Online Access: | https://os.copernicus.org/articles/19/1617/2023/os-19-1617-2023.pdf |
| _version_ | 1797461235371868160 |
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| author | P.-M. Poulain L. Centurioni C. Brandini S. Taddei M. Berta M. Menna |
| author_facet | P.-M. Poulain L. Centurioni C. Brandini S. Taddei M. Berta M. Menna |
| author_sort | P.-M. Poulain |
| collection | DOAJ |
| description | <p>An array of Lagrangian instruments (more than 100 drifters and a profiling float) were deployed for several days in the coastal waters of the southeastern Ligurian Sea to characterize the near-surface circulation at the submesoscale (<span class="inline-formula"><</span> 10 km). The drifters were trapped in an offshore-flowing filament and a cyclonic eddy that developed at the southwestern extremity of the filament. Drifter velocities are used to estimate differential kinematic properties (DKPs) and the relative dispersion of the near-surface currents on scales as small as 100 m. The maximum drifter speed is <span class="inline-formula">∼</span> 50 cm s<span class="inline-formula"><sup>−1</sup></span>. The DKPs within the cluster exhibit considerable spatial and temporal variability, with absolute values reaching the order of magnitude of the local inertial frequency. Vorticity prevails in the core of the cyclonic eddy, while strain is dominant at the outer edge of the eddy. Significant convergence was also found in the southwestern flow of the filament. The initial relative dispersion on small scales (100–200 m) is directly related to some of the DKPs (e.g., divergence, strain and instantaneous rate of separation). The mean squared separation distance (MSSD) grows exponentially with time, and the finite-size Lyapunov exponent (FSLE) is independent of scale. After 5–10 h of drift or for initial separations greater than 500 m, the MSSD and FSLE show smaller relative dispersion that decreases slightly with scale.</p> |
| first_indexed | 2024-03-09T17:16:31Z |
| format | Article |
| id | doaj.art-b762152d7cf446c29eb4cbfec9165407 |
| institution | Directory Open Access Journal |
| issn | 1812-0784 1812-0792 |
| language | English |
| last_indexed | 2024-03-09T17:16:31Z |
| publishDate | 2023-11-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Ocean Science |
| spelling | doaj.art-b762152d7cf446c29eb4cbfec91654072023-11-24T13:34:10ZengCopernicus PublicationsOcean Science1812-07841812-07922023-11-01191617163110.5194/os-19-1617-2023Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian SeaP.-M. Poulain0L. Centurioni1C. Brandini2S. Taddei3M. Berta4M. Menna5Centre for Maritime Research and Experimentation (CMRE), La Spezia, 19126, ItalyScripps Institution of Oceanography, La Jolla, 92093, California, USALaboratorio di Monitoraggio e Modellistica Ambientale per lo sviluppo sostenibile (LAMMA), CNR, Sesto Fiorentino, 50019, ItalyLaboratorio di Monitoraggio e Modellistica Ambientale per lo sviluppo sostenibile (LAMMA), CNR, Sesto Fiorentino, 50019, ItalyIstituto di Scienze Marine (ISMAR), CNR, La Spezia, 19032, ItalyIstituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS), Sgonico (Trieste), 34010, Italy<p>An array of Lagrangian instruments (more than 100 drifters and a profiling float) were deployed for several days in the coastal waters of the southeastern Ligurian Sea to characterize the near-surface circulation at the submesoscale (<span class="inline-formula"><</span> 10 km). The drifters were trapped in an offshore-flowing filament and a cyclonic eddy that developed at the southwestern extremity of the filament. Drifter velocities are used to estimate differential kinematic properties (DKPs) and the relative dispersion of the near-surface currents on scales as small as 100 m. The maximum drifter speed is <span class="inline-formula">∼</span> 50 cm s<span class="inline-formula"><sup>−1</sup></span>. The DKPs within the cluster exhibit considerable spatial and temporal variability, with absolute values reaching the order of magnitude of the local inertial frequency. Vorticity prevails in the core of the cyclonic eddy, while strain is dominant at the outer edge of the eddy. Significant convergence was also found in the southwestern flow of the filament. The initial relative dispersion on small scales (100–200 m) is directly related to some of the DKPs (e.g., divergence, strain and instantaneous rate of separation). The mean squared separation distance (MSSD) grows exponentially with time, and the finite-size Lyapunov exponent (FSLE) is independent of scale. After 5–10 h of drift or for initial separations greater than 500 m, the MSSD and FSLE show smaller relative dispersion that decreases slightly with scale.</p>https://os.copernicus.org/articles/19/1617/2023/os-19-1617-2023.pdf |
| spellingShingle | P.-M. Poulain L. Centurioni C. Brandini S. Taddei M. Berta M. Menna Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea Ocean Science |
| title | Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea |
| title_full | Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea |
| title_fullStr | Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea |
| title_full_unstemmed | Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea |
| title_short | Relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern Ligurian Sea |
| title_sort | relative dispersion and kinematic properties of the coastal submesoscale circulation in the southeastern ligurian sea |
| url | https://os.copernicus.org/articles/19/1617/2023/os-19-1617-2023.pdf |
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