Development and use of a very high resolution forecast model of the Tyrrhenian sea circulation
Corresponding people: ernesto napolitano , roberto iacono
The Tyrrhenian Sea is a critical area for the Italian conservation programs. Since the economy of the neighbouring regions strongly relies on sea transportation and on the use of coastal resources, the environmental impacts of these activities need to be carefully monitored. The effects of the environment on the human activities are also important, and need to be assessed.
The Tyrrhenian Sea is also a very interesting basin from the oceanographic point of view. It is characterized by a complex circulation (see, e.g Vetrano et al. , 2010), not yet fully understood, that is both driven by the exchanges occurring at its three openings (the Sardinia and Corsica Channels, and the Sicily Strait), and by the local atmospheric forcing.
In the context of the PRIMI Project (PRogetto pilota Inquinamento Marino da Idrocarburi), funded by the Italian Space Agency (ASI), we have recently developed a high-resolution operational model of the Tyrrhenian Sea, that provides daily forecasts of the circulation. The Tyrrhenian model is nested in a coarser resolution model of the whole Mediterranean circualtion (MFS, Tonani et al. 2008), run operationally by INGV.
Visualize current forecast
, to ,
The Tyrrhenian numerical model is based on POM (Princeton Ocean Model), a three-dimensional, hydrostatic, free-surface ocean model using sigma coordinates in the vertical direction (Blumberg and Mellor, 1987). It has a horizontal resolution of about 2 Km, and 40 vertical levels, and uses a realistic bathymetry, obtained from the U.S. DBDB1 (Navy Digital Batimetric Data Base), with a resolution of 1/60°. The Tyrrhenian model takes the initial condition and the time-dependent boundary conditions at the three openings from MFS (an optimal 3 to 1 ratio of horizontal grid spacing has been adopted), and is forced at the surface by momentum, heat, and salt fluxes computed with bulk formulae from ECMWF data.
Figure. Bathymetry with a resolution of 1/60°.
The forecast scheme is the following: on tuesday evening (11 pm) a 7 day forecast is issued, that is initialized seven days before with the father model, and uses analysis fields both for the boundary conditions and for the surface forcing. From wednesday to monday, the daily forecasts use as initial conditions the forecast of the previous day.
Figure. Forecast scheme.
References:
- Blumberg, A. and Mellor, G.: A Description of a Three-Dimensional Coastal Ocean Circulation Model, in: Three Dimensional Coastal Ocean Circulation Model, edited by Heaps, N., 1-16, American Geophysical Union, 1987. is forced at the surface by momentum, heat, and salt flux
- Tonani, M, N. Pinardi, S. Dobricic, I. Pujol, C. Fratianni, A High resolution free-surface model of the Mediterranean sea, Ocean Sci. 4,1-14, 2008
- Vetrano, A., E. Napolitano, R. Iacono, K. Schroeder, and G. P. Gasparini, Tyrrhenian Sea circulation and water mass fluxes in spring 2004: observations and model results, in press J. of Geoph. Res. (2010).