Evaluation of surface Lagrangian transport barriers in the Gulf of Trieste

F. Enrile, G. Besio, A. Stocchino, M. G. Magaldi, C. Mantovani, S. Cosoli, R. Gerin, P. M. Poulain

Research output: Journal article publicationJournal articleAcademic researchpeer-review

4 Citations (Scopus)

Abstract

The present work aims to detect Lagrangian transport barriers in the Gulf of Trieste by means of Lyapunov-exponent approach and tensorlines of the Cauchy-Green tensor. Lagrangian Coherent Structures (LCSs) are calculated employing 2D surface velocity fields measured by the coastal radars of the TOSCA EU research project (Tracking Oil Spills & Coastal Awareness Network). Moreover, surface drifters were deployed during the project. Comparisons between Eulerian velocity of HF-radar fields and Lagrangian velocity of drifters are carried out alongside single-particle tracking reliability. In particular, the possible influence of the data gaps in the HF-radar fields have been carefully considered. LCSs have proven to be robust against the quality of the starting HF-radar fields, leading to helpful insights in drifter positions. Indeed, after 24-hour integration the observed position of the drifter is approximately 1.5 km far from the nearest LCS, while a standard approach based on single-particle computations leads to larger errors (up to 5–7 km). However, such result must be properly interpreted taking into account the elongated nature of LCSs. A comparison between two common diagnostic tools of Lagrangian barriers is performed: Finite-Time and Finite-Size Lyapunov Exponent fields are compared in order to assess whether the patterns detected by the two measures are comparable. Finally, a joint analysis between LCSs and single-particle tracking is carried out and the results suggest that it would be desirable to couple these two approaches in real applications.

Original languageEnglish
Pages (from-to)125-138
Number of pages14
JournalContinental Shelf Research
Volume167
DOIs
Publication statusPublished - 1 Sep 2018
Externally publishedYes

Keywords

  • CODE drifters
  • FTLE and FSLE
  • Gulf of Trieste
  • Lagrangian Coherent Structures (LCS)
  • Single-particle tracking

ASJC Scopus subject areas

  • Oceanography
  • Aquatic Science
  • Geology

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