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.