### Abstract

Relative dispersion in the Liguro-Provençal basin (a subregion of the Mediterranean Sea) is investigated using clusters of surface drifters deployed during two Marine Rapid Environment Assessment (MREA) experiments covering different months in 2007 and 2008, respectively. The clusters have initial radii of less than 1km, or an order of magnitude below a typical deformation radius (approximately 10-20km). The data set consists of 45 original pairs and more than 50 total pairs (including chance ones) in the spatial range between 1 and 200km. Relative dispersion is estimated using the mean square separation of particle pairs and the Finite Scale Lyapunov Exponents (FSLEs). The two metrics show broadly consistent results, indicating in particular a clear exponential behaviour with an e-folding time scale between 0.5 and 1 days, or Lyapunov exponent λ in the range of 0.7-1 days^{-1}. The exponential phase extends for 4-7 days in time and between 1 and 10-20km in separation space. To our knowledge, this is only the third time that an exponential regime is observed in the world ocean from drifter data. This result suggests that relative dispersion in the Liguro-Provençal basin is nonlocal, namely controlled mainly by mesoscale dynamics, and that the effects of the sub-mesoscale motions are negligible in comparison. NCOM model results are used to complement the data and to quantify errors arising from the sparse sampling in the observations.

Original language | English (US) |
---|---|

Pages (from-to) | 209-228 |

Number of pages | 20 |

Journal | Deep-Sea Research Part I: Oceanographic Research Papers |

Volume | 58 |

Issue number | 3 |

DOIs | |

State | Published - Mar 2011 |

### Fingerprint

### Keywords

- Coastal transport.
- Dispersion
- Sub-mesoscale
- Turbulence

### ASJC Scopus subject areas

- Aquatic Science
- Oceanography

### Cite this

*Deep-Sea Research Part I: Oceanographic Research Papers*,

*58*(3), 209-228. https://doi.org/10.1016/j.dsr.2010.11.004

**Relative dispersion in the Liguro-Provençal basin : From sub-mesoscale to mesoscale.** / Schroeder, K.; Haza, A. C.; Griffa, A.; Ozgokmen, Tamay M; Poulain, P. M.; Gerin, R.; Peggion, G.; Rixen, M.

Research output: Contribution to journal › Article

*Deep-Sea Research Part I: Oceanographic Research Papers*, vol. 58, no. 3, pp. 209-228. https://doi.org/10.1016/j.dsr.2010.11.004

}

TY - JOUR

T1 - Relative dispersion in the Liguro-Provençal basin

T2 - From sub-mesoscale to mesoscale

AU - Schroeder, K.

AU - Haza, A. C.

AU - Griffa, A.

AU - Ozgokmen, Tamay M

AU - Poulain, P. M.

AU - Gerin, R.

AU - Peggion, G.

AU - Rixen, M.

PY - 2011/3

Y1 - 2011/3

N2 - Relative dispersion in the Liguro-Provençal basin (a subregion of the Mediterranean Sea) is investigated using clusters of surface drifters deployed during two Marine Rapid Environment Assessment (MREA) experiments covering different months in 2007 and 2008, respectively. The clusters have initial radii of less than 1km, or an order of magnitude below a typical deformation radius (approximately 10-20km). The data set consists of 45 original pairs and more than 50 total pairs (including chance ones) in the spatial range between 1 and 200km. Relative dispersion is estimated using the mean square separation of particle pairs and the Finite Scale Lyapunov Exponents (FSLEs). The two metrics show broadly consistent results, indicating in particular a clear exponential behaviour with an e-folding time scale between 0.5 and 1 days, or Lyapunov exponent λ in the range of 0.7-1 days-1. The exponential phase extends for 4-7 days in time and between 1 and 10-20km in separation space. To our knowledge, this is only the third time that an exponential regime is observed in the world ocean from drifter data. This result suggests that relative dispersion in the Liguro-Provençal basin is nonlocal, namely controlled mainly by mesoscale dynamics, and that the effects of the sub-mesoscale motions are negligible in comparison. NCOM model results are used to complement the data and to quantify errors arising from the sparse sampling in the observations.

AB - Relative dispersion in the Liguro-Provençal basin (a subregion of the Mediterranean Sea) is investigated using clusters of surface drifters deployed during two Marine Rapid Environment Assessment (MREA) experiments covering different months in 2007 and 2008, respectively. The clusters have initial radii of less than 1km, or an order of magnitude below a typical deformation radius (approximately 10-20km). The data set consists of 45 original pairs and more than 50 total pairs (including chance ones) in the spatial range between 1 and 200km. Relative dispersion is estimated using the mean square separation of particle pairs and the Finite Scale Lyapunov Exponents (FSLEs). The two metrics show broadly consistent results, indicating in particular a clear exponential behaviour with an e-folding time scale between 0.5 and 1 days, or Lyapunov exponent λ in the range of 0.7-1 days-1. The exponential phase extends for 4-7 days in time and between 1 and 10-20km in separation space. To our knowledge, this is only the third time that an exponential regime is observed in the world ocean from drifter data. This result suggests that relative dispersion in the Liguro-Provençal basin is nonlocal, namely controlled mainly by mesoscale dynamics, and that the effects of the sub-mesoscale motions are negligible in comparison. NCOM model results are used to complement the data and to quantify errors arising from the sparse sampling in the observations.

KW - Coastal transport.

KW - Dispersion

KW - Sub-mesoscale

KW - Turbulence

UR - http://www.scopus.com/inward/record.url?scp=79951810039&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79951810039&partnerID=8YFLogxK

U2 - 10.1016/j.dsr.2010.11.004

DO - 10.1016/j.dsr.2010.11.004

M3 - Article

VL - 58

SP - 209

EP - 228

JO - Deep-Sea Research Part I: Oceanographic Research Papers

JF - Deep-Sea Research Part I: Oceanographic Research Papers

SN - 0967-0637

IS - 3

ER -