Optimal design of a lagrangian observing system for hydrodynamic surveys

In this paper the problem of the optimisation of at-sea campaigns is tackled throughout the implementation of a near real-time decision support system (DSS) for short-term Lagrangian observing platforms. The DSS consisted of two modules: a real-time coastal-ocean forecasting system (CFS), including both hydrodynamic and particle-tracking numerical models, and a module to provide optimised deployment solutions for a set of Lagrangian current-meter buoys. The system was calibrated for a shallow water environment -the Cabras Lagoon in the western Mediterranean Sea. The DSS was then applied to provide in situ optimised measurement strategies during a Lagrangian survey campaign. The different solutions provided by the DSS were verified by real-time measurements and the system was established to be efficient in reducing the cost-benefit ratio and favouring long records and near-synoptic and nonredundant observations.