Ocean Dynamics

, Volume 60, Issue 4, pp 861–882 | Cite as

Transport properties in small-scale coastal flows: relative dispersion from VHF radar measurements in the Gulf of La Spezia

  • Angelique C. Haza
  • Tamay M. ÖzgökmenEmail author
  • Annalisa Griffa
  • Anne Molcard
  • Pierre-Marie Poulain
  • Germana Peggion


Lagrangian transport characteristics in the Gulf of La Spezia, a 5 × 10-km area along the western coast of Italy, are investigated using data collected from a very high frequency (VHF) radar system with 250 m and 30-min resolution and two clusters of Coastal Dynamics Experiment surface drifters during 2 weeks in the summer of 2007. The surface drifters are found to follow the temporal and spatial evolution of the finite-scale Lyapunov exponents (FSLEs) computed by the VHF radar, indicating the precision of both the radar measurements and the diagnostic FSLE in mapping accurately the transport pathways. In light of this agreement, an analysis of the relative dispersion is conducted. It is found that the average FSLE value varies within a narrow range of \(4 \;\mbox{day}^{-1} \leq \lambda \leq 7 \;\mbox{day}^{-1}\) and displays an exponential regime over the entire extent of the measurements. The dynamical implication is that relative dispersion is controlled nonlocally, namely by slow, persistent, energetic mesoscale structures as opposed to the rapidly evolving high-gradient small-scale turbulent features. The value of the exponent is about an order of magnitude larger than those found in previous modeling studies and analysis of SCULP data in the Gulf of Mexico but somewhat smaller than that estimated from CLIMODE drifters in the Gulf Stream region. Scaling of the FSLE using a metric of resolved gradients of the Eulerian fields in the form of a positive Okubo–Weiss criterion is useful, but not as precise as in modeling studies. The horizontal flow convergence is found to have a small yet tangible effect on relative dispersion.


Relative dispersion FSLE Lagrangian coherent structures VHF radar Coastal turbulence 



We are grateful to ONR via grants N00014-05-1-0094 and N00014-05-1-0095 (Haza, Özgökmen, Griffa), N00014-08-2-1146 and N00173-07-2-C901 (Peggion), and to EC through the ECOOP project (Griffa). We wish to acknowledge the contribution form the NRL scientific team with special thanks to Dr. C. Rowley and Mr. R. Allard and Dr E. Coelho. We also thank A. Lisca for sharing the data from the ENEA meteo station.


  1. Aref H (1984) Stirring by chaotic advection. J Fluid Mech 192:115–173Google Scholar
  2. Artale V, Boffetta G, Celani A, Cencini M, Vulpiani A (1997) Dispersion of passive tracers in closed basins: beyond the diffusion coefficient. Phys Fluids 9:3162–3171CrossRefGoogle Scholar
  3. Astraldi M, Gasparini G, Manzella G (1990) Temporal variability of currents in the eastern Ligurian Sea. J Geophys Res 95(C2):1515–1522CrossRefGoogle Scholar
  4. Aurell E, Boffetta G, Crisanti A, Paladin G, Vulpiani A (1997) Predictability in the large: an extension of the concept of Lyapunov exponent. J Phys A 30:1–26CrossRefGoogle Scholar
  5. Barbin Y, Broche P, de Maistre J-C, Forget P, Gaggelli J (2006) Practical results of direction finding method applied on a 4 antenna linear array WERA. ROW-6 Radiowave Oceanography WorkshopGoogle Scholar
  6. Barrick D, Lipa BJ (1986) The second-order shallow water hydrodynamic coupling coefficient in interpretation of HF radar sea echo. IEEE J Oceanic Eng OE-11:310–315CrossRefGoogle Scholar
  7. Bauer S, Swenson M, Griffa A (2002) Eddy mean flow decomposition and eddy diffusivity estimates in the tropical Pacific Ocean: 2. Results. J Geophys Res 107:C10. doi: 10.1029/2000JC000613 CrossRefGoogle Scholar
  8. Bennett AF (1984) Relative dispersion—local and nonlocal dynamics. J Atmos Sci 41(11):1881–1886CrossRefGoogle Scholar
  9. Berloff P, McWilliams J (2002) Material transport in oceanic gyres. Part 2: hierarchy of stochastic models. J Phys Oceanogr 32/3:797–830CrossRefGoogle Scholar
  10. Boccaletti G, Ferrari R, Fox-Kemper B (2007) Mixed layer instabilities and restratification. J Phys Oceanogr 37:2228–2250CrossRefGoogle Scholar
  11. Bordone A, Lisca A (2009) Meteorological data from the ENEA station of S.Teresa (sp). RT ENEA/2009/15/ACSGoogle Scholar
  12. Broche P, Barbin Y, De Maistre J-C, Forget P, Gaggelli J (2004) Antennas processing and design for VHF COSMER coastal radar. ROW-4 Radiowave Oceanography WorkshopGoogle Scholar
  13. Castellari S, Griffa A, Özgökmen T, Poulain P-M (2001) Prediction of particle trajectories in the Adriatic Sea using Lagrangian data assimilation. J Mar Syst 29:33–50CrossRefGoogle Scholar
  14. Coulliette C, Wiggins S (2000) Intergyre transport in a wind-driven, quasigeostrophic double gyre: an application of lobe dynamics. Nonlinear Process Geophys 7:59–85CrossRefGoogle Scholar
  15. Craik A, Leibovich S (1976) A rational model for Langmuir circulations. J Fluid Mech 73:401–426CrossRefGoogle Scholar
  16. Davis R (1985) Drifter observations of coastal currents during CODE. The method and descriptive view. J Geophys Res 90:4741–4755CrossRefGoogle Scholar
  17. Davis R (1991) Observing the general-circulation with floats. Deep-Sea Res 38:531–571CrossRefGoogle Scholar
  18. d’Ovidio F, Fernandez V, Hernandez-Garcia E, Lopez C (2004) Mixing structures in the Mediterranean Sea from finite-size Lyapunov exponents. Geophys Res Lett 31:L17203. doi: 10.1029/2004GL020328 CrossRefGoogle Scholar
  19. Essen H-H, Gurgel K-W, Schlick T (2000) On the accuracy of current measurements by means of HF radar. IEEE J Oceanic Eng 25:472–480CrossRefGoogle Scholar
  20. Falco P, Griffa A, Poulain P, Zambianchi E (2000) Transport properties in the Adriatic Sea as deduced from drifter data. J Phys Oceanogr 30:2055–2071CrossRefGoogle Scholar
  21. Fratantoni D (2001) North Atlantic surface circulation during the 1990’s observed with satellite-tracked drifters. J Geophys Res 106:22067–22093CrossRefGoogle Scholar
  22. Gasparini G, Abbate M, Bordone A, Cerrati G, Galli C, Lazzoni E, Negri A (2009) Circulation and biomass distribution during warm season in the Gulf of La Spezia (north-western Mediterranean). J Mar Syst 78/1:S48–S62CrossRefGoogle Scholar
  23. Griffa A (1996) Applications of stochastic particle models to oceanographic problems. In: Adler R, Müller P, Rozovskii B (eds) Stochastic modelling in physical oceanography, vol 467. Birkhauser, Boston, pp 113–128Google Scholar
  24. Griffa A, Lumpkin R, Veneziani M (2008) Cyclonic and anticyclonic motion in the upper ocean. Geophys Res Lett 35:L01608. doi: 10.1029/2007GL032100 CrossRefGoogle Scholar
  25. Gurgel K-W, Antonischski G, Essen H-H, Schlick T (1999) Wellen radar (WERA): a new ground wave radar for remote sensing. Coast Eng 37:219–234CrossRefGoogle Scholar
  26. Haller G (1997) Distinguished material surfaces and coherent structures in three-dimensional flows. Physica D 149/4:248–277Google Scholar
  27. Haller G, Poje A (1998) Finite time transport in aperiodic flows. Physica D 119:352–380CrossRefGoogle Scholar
  28. Haza AC, Griffa A, Martin P, Molcard A, Özgökmen TM, Poje AC, Barbanti R, Book JW, Poulain PM, Rixen M, Zanasca P (2007) Model-based directed drifter launches in the Adriatic Sea: results from the DART experiment. Geophys Res Lett 34:L10605. doi: 10.1029/2007GL029634 CrossRefGoogle Scholar
  29. Haza AC, Poje A, Özgökmen TM, Martin P (2008) Relative dispersion from a high-resolution coastal model of the Adriatic Sea. Ocean Model 22:48–65Google Scholar
  30. Kaplan D, Largier J, Botsford L (2005) HF radar observations of surface circulation off Bodega Bay (northern California, USA). J Geophys Res 110:C10020. doi: 10.1029/2005JC002959 CrossRefGoogle Scholar
  31. LaCasce J, Bower A (2000) Relative dispersion in the subsurface North Atlantic. J Mar Res 58:863–894CrossRefGoogle Scholar
  32. LaCasce JH, Ohlmann C (2003) Relative dispersion at the surface of the Gulf of Mexico. J Mar Res 61(3):285–312CrossRefGoogle Scholar
  33. Lacorata G, Aurell E, Vulpiani A (2001) Drifter dispersion in the Adriatic Sea: Lagrangian data and chaotic model. Ann Geophys 19:121–129CrossRefGoogle Scholar
  34. Langmuir I (1938) Surface motion of water induced by wind. Science 41:119–123CrossRefGoogle Scholar
  35. Lesieur M (1997) Turbulence in fluids. In: Fluid mechanics and its applications, vol 40. Kluwer Academic, AmsterdamGoogle Scholar
  36. Lumpkin R, Ellipot S (2010) Surface drifter pair spreading in the North Atlantic. J Geophys Res (in press)Google Scholar
  37. Mahadevan A (2006) Modeling vertical motion at ocean fronts: are nonhydrostatic effects relevant at submesoscales? Ocean Model 14:222–240CrossRefGoogle Scholar
  38. Martin PJ (2000) Description of the navy coastal ocean model version 1.0. Naval Research Laboratory report, RL/FR/7322-00-9962, 42 ppGoogle Scholar
  39. McWilliams JC (1985) Submesoscale, coherent vortices in the ocean. Rev Geophys 23(2):165–182CrossRefGoogle Scholar
  40. McWilliams JC (2003) Diagnostic force balance and its limits. In: Nonlin. proc. geophys. fluid dyn., pp 287–304Google Scholar
  41. Miller P, Pratt L, Helfrich K, Jones C (2002) Chaotic transport of mass and potential vorticity for an island recirculation. J Phys Oceanogr 32:80–102CrossRefGoogle Scholar
  42. Molcard A, Poje A, Özgökmen T (2006) Directed drifter launch strategies for Lagrangian data assimilation using hyperbolic trajectories. Ocean Model 12:268–289CrossRefGoogle Scholar
  43. Molcard A, Poulain P, Forget P, Griffa A, Barbin Y, Gaggeli J, Maistre JD, Rixen M (2009) Comparison between VHF radar observations and data from drifter clusters in the Gulf of La Spezia (Mediterranean Sea). J Mar Syst 78/1:S78–S89Google Scholar
  44. Molemaker M, McWilliams J (2005) Baroclinic instability and loss of balance. J Phys Oceanogr 35:1505–1517CrossRefGoogle Scholar
  45. Ohlmann C, White P, Washburn L, Terrill E, Emery B, Otero M (2007) Interpretation of coastal HF radar-derived surface currents with high-resolution drifter data. J Atmos Ocean Technol 24/4:666–680CrossRefGoogle Scholar
  46. Okubo A (1970) Horizontal dispersion of floatable particles in vicinity of velocity singularities such as convergences. Deep-Sea Res 17(3):445–454Google Scholar
  47. Olascoaga M, Rypina II, Brown MG, Beron-Vera FJ, Kocak H, Brand LE, Halliwell GR, Shay LK (2006) Persistent transport barrier on the West Florida Shelf. Geophys Res Lett 33:22603. doi: 10.1029/2006GL027800 CrossRefGoogle Scholar
  48. Ottino J (1989) The kinematics of mixing: stretching, chaos and transport. Cambridge University Press, CambridgeGoogle Scholar
  49. Özgökmen T, Griffa A, Piterbarg L, Mariano A (2000) On the predictability of Lagrangian trajectories in the ocean. J Atmos Ocean Technol 17:366–383CrossRefGoogle Scholar
  50. Özgökmen T, Piterbarg L, Mariano A, Ryan E (2001) Predictability of drifter trajectories in the tropical Pacific Ocean. J Phys Oceanogr 31:2691–2720CrossRefGoogle Scholar
  51. Paduan J, Kim K, Cook M, Chavez F (2006) Calibration and validation of direction finding high frequency radar ocean current observations. IEEE J Oceanic Eng 31(4):862–875. doi: 10.1109/JOE.2006.886195 CrossRefGoogle Scholar
  52. Paduan J, Rosenfeld L (1996) Remotely sensed surface currents in Monterey Bay from shore based HF radar (Coastal ocean dynamics application radar). J Geophys Res 101/C9:20669–20686CrossRefGoogle Scholar
  53. Poje A, Haller GG (1999) Geometry of cross-stream mixing in a double-gyre ocean model. J Phys Oceanogr 29:1649–1665CrossRefGoogle Scholar
  54. Poje A, Haza A, Özgökmen T, Magaldi M, Garraffo Z (2010) Resolution dependent relative dispersion statistics in a hierarchy of ocean models. Ocean Model 31:36–50CrossRefGoogle Scholar
  55. Poje AC, Toner M, Kirwan AD, Jones CKRT (2002) Drifter launch strategies based on Lagrangian templates. J Phys Oceanogr 32:1855–1869CrossRefGoogle Scholar
  56. Poulain P-M (1999) Drifter observations of surface circulation in the Adriatic Sea between December 1994 and March 1996. J Mar Syst 20:231–253CrossRefGoogle Scholar
  57. Richardson P (2001) Drifters and floats. In: Encyclopedia of ocean studies, vol 2, pp 767–774Google Scholar
  58. Schott F, Frisch S, Larsen J (1986) Comparison of surface currents measured by HF Doppler Radar in the western Florida Straits during November 1983 to January 1984 and Florida Current transport. J Geophys Res 91:8451–8460CrossRefGoogle Scholar
  59. Shadden S, Lekien F, Paduan JD, Chavez FC, Marsden JE (2008) The correlation between surface drifters and coherent structures based on high-frequency data in Monterey Bay. Deep-Sea Res II 56:161–172CrossRefGoogle Scholar
  60. Shay L, Lentz S, Graber H, Haus B (1998a) Current structure variations detected by high frequency radar and vector measuring current meters. J Atmos Ocean Technol 15:237–256CrossRefGoogle Scholar
  61. Shay L, Lee T, Williams E, Graber H, Rooth C (1998b) Effects of low frequency current variability on submesoscale near-inertial vortices. J Geophys Res 103:18691–18714CrossRefGoogle Scholar
  62. Shay L, Cook T, Hallock Z, Haus B, Graber H, Martinez J (2001) The strength of the M2 tide at the Chesapeake Bay mouth. J Phys Oceanogr 31:427–449CrossRefGoogle Scholar
  63. Shay L, Martinez-Pedraja J, Cook T, Haus B (2007) High-frequency radar mapping of surface currents using WERA. J Atmos Ocean Technol 24:484–503CrossRefGoogle Scholar
  64. Skyllingstad ED, Denbo D (1995) An ocean large-eddy simulation of Langmuir circulations and convection in the surface mixed layer. J Geophys Res 100:8501–8522CrossRefGoogle Scholar
  65. Steward R, Joy J (1974) HF radio measurements of surface currents. Deep-Sea Res 21:1039–1049Google Scholar
  66. Thomas LN, Tandon A, Mahadevan A (2008) Sub-mesoscale processes and dynamics. In Hecht MW, Hasumi H (eds) Ocean modeling in an eddying regime, geophysical monograph series, vol 177. American Geophysical Union, Washington DC, pp 17–38Google Scholar
  67. Toner M, Poje AC (2004) Lagrangian velocity statistics of directed launch strategies in a Gulf of Mexico model. Nonlinear Process Geophys 11:35–46CrossRefGoogle Scholar
  68. Ullman D, O’Donnell J, Kohut J, Fake T, Allen A (2006) Trajectory prediction using HF radar surface currents: Monte Carlo simulations of prediction uncertainties. J Geophys Res 111:C12005. doi: 10.1029/2006JC003715 CrossRefGoogle Scholar
  69. Vandenbulcke L, Beckers J, Lenartz F, Barth A, Poulain P, Aidonidis M, Meyrat J, Ardhuin F, Tonani M, Fratianni C, Torrisi L, Pallela D, Chiggiato J, Tudor M, Book JW, Martin P, Peggion G, Rixen M (2009) Super-ensemble techniques: application to surface drift prediction during the DART06 and MREA07 campaigns. Prog Oceanogr 82:149–167CrossRefGoogle Scholar
  70. Veneziani M, Griffa A, Garraffo Z, Chassignet E (2005a) Lagrangian spin parameter and coherent structures from trajectories released in a high-resolution ocean model. J Mar Res 63/4:753–788CrossRefGoogle Scholar
  71. Veneziani M, Griffa A, Reynolds A, Garraffo Z, Chassignet E (2005b) Parameterizations of Lagrangian spin statistics and particle dispersion in the presence of coherent vortices. J Mar Res 63/6:1057–1083CrossRefGoogle Scholar
  72. Weiss J (1991) The dynamics of enstrophy transfer in 2-dimensional hydrodynamics. Physica D 48(2–3):273–294CrossRefGoogle Scholar
  73. Weller R, Price J (1988) Langmuir circulation within the oceanic mixed layer. Deep-Sea Res 35:711–747CrossRefGoogle Scholar
  74. Wiggins S (2005) The dynamical systems approach to Lagrangian transport in oceanic flows. Ann Rev Fluid Mech 37:295–328CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2010

Authors and Affiliations

  • Angelique C. Haza
    • 1
  • Tamay M. Özgökmen
    • 1
    Email author
  • Annalisa Griffa
    • 1
    • 2
  • Anne Molcard
    • 3
  • Pierre-Marie Poulain
    • 4
  • Germana Peggion
    • 5
  1. 1.RSMAS/MPOUniversity of MiamiMiamiUSA
  2. 2.ISMAR-CNRLa SpeziaItaly
  3. 3.LSEETUniversity of ToulonToulonFrance
  4. 4.OGSTriesteItaly
  5. 5.University of Southern MississippiHattiesburgUSA

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