HR: 0800h
AN: GC21A-0144    [Abstracts]
TI: A Regional Ocean Climate Model for the Mediterranean Sea With a Two-way Grid Refinement at the Strait of Gibraltar
AU: Artale, V
EM: artale@casaccia.enea.it
AF: ENEA, Via Anguillarese, 301, Rome, 00123, Italy
AU: * Sannino, G
EM: gianmaria.sannino@casaccia.enea.it
AF: ENEA, Via Anguillarese, 301, Rome, 00123, Italy
AU: Carillo, A
EM: adriana.carillo@casaccia.enea.it
AF: ENEA, Via Anguillarese, 301, Rome, 00123, Italy
AU: Ruggiero, V
EM: vittorio.ruggiero@caspur.it
AF: CASPUR, via dei Tizii, 6, Rome, 00185, Italy
AB: The Mediterranean Sea is connected to the Atlantic ocean through the Strait of Gibraltar, a narrow and shallow channel, 60 km long and 20 km wide, characterized by a complex system of contractions and sills. The mean circulation within the strait of Gibraltar is an inverse estuarine circulation, characterized by a two-way exchange, with an upper flow of fresh and warm Atlantic water spreading in the Mediterranean basin, and a lower flow of cold and salty Mediterranean water sinking in the North Atlantic down to a depth of around 1000 m where it becomes neutrally buoyant. While this mean circulation is driven by an excess of evaporation over precipitation and river runoff in the Mediterranean sea, its magnitude and hydrological properties strongly depend on the physical configuration of the strait. In fact, it is well known that the water exchange within the strait, is subject to hydraulic control. The actual Mediterranean Sea regional models are typically characterized by an horizontal resolution ranging from 1/8^o up to 1/16^o. These resolutions are not able to describe the complex bathymetry of the strait, and so they are not able to reproduce the correct two-way exchange in terms of heat, salt and volume fluxes. To overcome this issue we apply the two-way grid refinement technique to the strait region; in particular the whole Mediterranean basin has been implemented using the MITgcm at 1/8^o×1/8^o (the ocean model component of the Protheus system), while the same model in the strait region reaches a finer resolution of 1/24^o. Here we stress that 1/24^o is the minimum resolution needed to represent in a reasonable way all the bathymetric features of the strait. In order to evidence the influence of the strait dynamics on the internal Mediterranean thermohaline circulation, two experiments, reproducing the actual climate conditions, were performed with and without grid-refinement. Results from these two experiments will be presented in detail and the major differences will be discussed.
DE: 0545 Modeling (4255)
DE: 1637 Regional climate change
DE: 4243 Marginal and semi-enclosed seas
DE: 4553 Overflows
DE: 4568 Turbulence, diffusion, and mixing processes (4490)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting