Ocean Forecasting
The capability of accurately predicting the ocean system in terms of wave motion, currents and temperature and salinity stratification is crucial not only to increase our knowledge of the ocean but also for several important practical applications, such as navigation, search and rescue operations, littoral activities, ecosystem managing, and accident response and mitigation, for instance in case of pollutant releases (oil spills). When facing the necessity of tracking a generic drifting object, direct observations may not be available to provide details of the spatial and temporal distribution of the driving currents; when available, however, they are generally not sufficient, particularly for large areas. This is the reason why we usually rely on circulation fields produced by dynamical, state-of-the-art numerical models of the ocean, atmosphere and sea state. In order to provide useful products, these fields need to be as accurate as possible.
ISMAR has an extensive expertise in many aspects of operational oceanography, and in particular plays an international role in the development and implementation of wind-wave models and in the prediction of transport by ocean currents.
The wave prediction system is carried out in ISMAR mainly by using two numerical tools, WAM and SWAN (www.swan.tudelft.nl/), forced by wind and pressure fields from global models or limited area ones (e.g. www.cosmo-model.org/). ISMAR is responsible and issues daily, in collaboration with the CNMCA, the “sea-state forecast” for the Italian and the whole Mediterranean seas
(http://ricerca.ismar.cnr.it/MODELLI/ONDE_MED_ITALIA/pagehtml/nettuno/NETTUNO2.html).
In addition, ISMAR has a large and recognized experience calibrating and validating these numerical outputs, by means of including satellite and in situ data (e.g. wind and wave measurements at the Platform “Acqua Alta”). Starting from the resulting time series it is possible to evaluate the wave energy that is transferring to the coast, and more specifically its extreme value and return time. These fundamental information are then used into integrated numerical models to hindcast or predict erosion/modification trends of the coast line.
In the field of transport prediction by ocean currents, ISMAR has developed and implemented a number of new methods to improve the prediction of the motion of quantities transported by ocean currents, based on the joint use of numerical models and experimental data. The work has been funded by European (MFSTEP) and international (ONR) projects, and carried out in strict collaboration with a group of international researchers, the LAPCOD (Lagrangian Analysis and Prediction of the Coastal Ocean) group (www.rsmas.miami.edu/LAPCOD). Methods from dynamical systems have been used to identify the main transport “barriers” associated to the currents, and applications have been carried out in the Adriatic and Ligurian Seas using model results together with data from drifters and HF radars. New “assimilation” methods have been developed to improve model results using in-situ and satellite data. In particular, the assimilation of position data from Argo floats is presently in the process of been transitioned to operational systems such as the MFS (Mediterranean Forecasting System).
