Abstract

Floating tracer clustering is studied in oceanic flows that combine both a field of coherent mesoscale vortices simulated by a regional, comprehensive, eddy-resolving general circulation model and randomly modeled submesoscale velocity fields. Both fields have rotational and divergent velocity components, and depending on their relative contributions as well as on the local characteristics of the mesoscale vortices, we reported different clustering scenarios. We found that inclusion of the mesoscale vortices does not prevent clustering, but the rates and patterns of clustering become significantly modified. We also demonstrated that even when the surface velocity divergence is weak, it has to be taken into account to avoid significant errors in model predictions of the floating tracer patterns. Our approach combining dynamically constrained and random velocity fields, and the applied diagnostic methods, are proposed as standard tools for analyses and predictions of floating tracer distributions, both in observational data and general circulation models.