title: Finite-time compressibility as an agent of frequent spontaneous patch formation in the surface layer: A case study for the Gulf of Finland, the Baltic Sea.
abstract: We explore the possibilities for spontaneous formation of surface patches with high concentrations of contaminants through time correlations of the convergence field and the Lagrangian transport. The test area is the Gulf of Finland, the Baltic Sea, where surface velocity fields show extensive convergence. The flow properties are extracted from 3D velocity fields simulated for 1987-1991 using the OAAS model with a resolution of 1 mile. The focus is on the spatial distribution of the areas in which the values of finite-time flow compressibility of surface velocity fields exceed the threshold for clustering of floats. The distribution of such areas is asymmetric, with likely areas of patch formation located predominantly in the southern and eastern regions of the gulf. Out of nine areas of likely patch formation, six are located along the coast in regions of frequent downwelling, while three are identified in the central region of the gulf.
authors.affiliation: Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn, Estonia. Electronic address: andrea@cens.ioc.ee.
authors.forename: Andrea
authors.initials: A
authors.lastname: Giudici
authors.affiliation: Institute of Cybernetics at Tallinn University of Technology, Akadeemia tee 21, 12618 Tallinn, Estonia; Estonian Academy of Sciences, Kohtu 6, 10130 Tallinn, Estonia.
authors.forename: Tarmo
authors.initials: T
authors.lastname: Soomere
mesh_terms: D001454:Baltic States; D005387:Finland; D008962:Models, Theoretical; D012623:Seawater / Q000737:chemistry*; D014872:Water Movements; D014876:Water Pollution
keywords: Baltic Sea; Flow compressibility; Lagrangian transport; Maritime pollution; Patch formation; Pollution control