Numerical forecast of the sea state in the western Mediterranean and coastal waters

Western Mediterranean Forecast available from to Click on the picture to access the forecast

Oristano Coastal Waters Forecast available from to Click on the picture to access the forecast

This is an electronic report for the daily numerical forecast of the sea state in the western Mediterranean Sea (hydrodynamics, waves) produced at a spatial resolution of 3 km and in the Oristano coastal waters (central Sardinian Sea) by the WMED system.

Overview - Western Mediterranean Forecast -

The numerical simulation system of the marine circulation at regional scale (3 km) of the seas around Sardinia gives a daily forecast, to maximum 5 days, of some hydrodynamical mean fields (temperature, salinity, speed and other physical parameters) starting from 00:00 UTC. The system is operative since February 2005. The simulation numerical model is based on the 3D ocean circulation model called POM (Princeton Ocean Model developed by Blumberg and Mellor, 1987) and is numerically coupled to lateral boundaries with the simulation numerical model of the whole Mediterranean circulation (MFSTEP-OGCM), developed at the Dynamics and Climatology Unit of the INGV in Bologna (Pinardi et al., 2005). The numerical coupling is one-way asynchronously nested. At the surface boundary the forecast numerical model at regional scale is forced through momentum fluxes, heat and "water" calculated by the hourly fields of the atmospheric parameters (wind speed, wind direction, humidity, cloud coverage, solar radiation, etc.). These parameters are simulated by the forecast numerical model at high spatial resolution (10 km) of the atmospheric circulation (called Skiron), developed at the Atmospheric Modeling & Weather Forecasting Group of the Athens University (Kallos et al., 2004). The calculation of fluxes at the air-sea interface is realised asynchronously by the use of an interactive algorithm based on the bulk formulae. The forecasting numerical system works in Slave Mode and Near-Real-Time, i.e. the simulation model is daily re-initialized by using the daily numerical fields produced by the numerical simulation model at basin scale (5 km) MFSTEP-OGCM. Near-Real-Time means that "assimilated" data are available within 3 days from the real acquisition date of the data. Due to acquisition and calculation times, the forecast is realised with a late of about 15 hours. The POMO (Wave Predictions of the western Mediterranean) system is based on the 3rd generation wave model named WaveWatch3. It covers Tyrrhenian and Ligurian seas, and the Sardinian Channel and Sea, with a spatial resolution of about 7 km. Every day it produces 5-days forecasts of wave height, direction, length and period. At surface it is coupled with the amospheric model Skiron LAM2 that gives wind and air temperature, and with the ocean model WMED that gives sea currents and water temperature.

- Oristano coastal waters -

The numerical simulation system of the coastal circulation provides a daily forecast, to maximum 3 days, of the barotropic current velocities in the Oristano Gulf, Lagoon systems and in the surrounding coastal areas. The core of the forecasting system is the SHYFEM, a finite element hydrodynamic numerical model that has been already validated and calibrated in the Oristano Gulf and Lagoon system in previous studies (Cucco et al., 2006, Ferrarin et al., 2004). Such a model well reproduces the tide and wind induced water circulation in the study area where it is applied in its 2D version in order to reproduce the barotropic current velocities. Numerical simulations are carried out over a computational domain that represents the area between 8°15' and 8°35' of longitude E and, 39°40' and 40°05' of latitude N, by means of a finite element staggered grid (figure 1, 2). The numerical grid consists of 21602 nodes and 40068 triangular elements and is characterized by different spatial resolutions varying from 10m, for the smallest channels connecting the Cabras lagoon and the Oristano Gulf, to few kms in the off-shore areas of the Sardinian Sea. The model considers the off-shore perimeter of the computational domain as open boundary. The model is forced by an astronomic tide imposed at the open boundary and by a wind intensity and direction imposed as surface boundary condition. Meteorological data are provided by atmospheric simulations carried out at the Athens University by means of SKYRON atmospheric numerical model.

	Contact		In Sardu		Versione Italiana
	Dr Roberto Sorgente IAMC-CNR Oristano, c\o IMC, Loc. Sa Mardini, 09072 Torregrande, Oristano, Italy           tel. +39.0783.22027/22136/22032 fax +39.0783.22002  email: [name.surname]@iamc.cnr.it

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