Presentation of the tools developed (part 1)

How to optimize the drifters deployment strategy?

-> Enrico ZAMBIANCHI, DISAM

Presentation of the tools developed (part 1)

Large scale flow(several info sources)

Small scale flow(almost only drifters)

2 different issues

Large-scale flow

≤ Ro ~ 5 km for coastalMediterranean

areas

No info

[Ro is the typical scale of eddies and mesoscale flow features]

Large-scale flowHow can we gain some info?

Some prior (or current) knowledge may be

extremely useful,

or even crucial…

Large-scale flow

Large-scale flow

Large-scale flowbut…

but…

Large-scale flow

Some prior knowledge may be extremely useful,

or even crucial…

Large-scale flow

Some prior knowledge may be extremely useful,

or even crucial…

Large-scale flow

Large-scale flowPrior/current knowledge possible sources (need for synopticity)

ad hoc drifter deployments•past observations of repetitive patterns•knowledge of specific dynamical situations (fronts, LCSs)•HF radar data

Redeployment is highly recommended

Large-scale flow

Redeployment is highly recommended

Large-scale flow

Large-scale flow

LS flow - RecommendationsPrior or initial knowledge required – if missing, plan individual deployments to get an idea of LS flowDistance between deployments ≤ Ro (~ 4-5 km)Deployments on a regular grid, if necessary adapted to specific flow patterns/regimes (fronts, eddies, connecting paths)If constrained by budget and/or logistics, spare drifters in order to redeploy

LS flow – add’l recommendIf you have people running a model or collecting synoptic data, ASK THEM

(the Ro rule of thumb stands anyway)

By-recommendation: study your areas as intensively as you can, install as many radar systems as you can, get yourself a good forecast model…

LS flow: one special issueIn coastal areas several “interesting” features may occur:Lagrangian Coherent Structures are barriers to transport, created by the velocity field. They separate neighbouring sub-areas of a basin which do not exchange fluid with each other, thus limiting the effectiveness of water renewal processes.(the first LCS-targeted massive drifter experiment ever was organized within TOSCA)

Small-scale = subgrid scale,

controls the spreading

Small-scale flow

Relative dispersionAre sub-mesoscale processes (i.e. processes at scales less than Ro) important?

Relative dispersion measures the separation between pairs of particles

50 m

50 m

50 m

Naples , Toulon and Trieste deployment strategies

Relative = particle pair separation

SS flow - RecommendationAlong with the deployments planned for the Large-Scale flow

deploy triplets!

anywhere in the field, and in particular if there are fronts or other interesting structures

Thanks for attendingTOSCA Final Meeting!