|
...descentrada Arakawa C, con resolución de 41.5 km en x y 39 km en y. Los resultados del modelo reproducen los giros ciclónicos del Mar Tirreno, del Mar Ligurio y de la región que se encuentra entre la cuenca de Argelia y la parte occidental de las islas Baleares. La solución muestra la circulación anticiclónica de la Planicie Abisal, de la cuenca de Argelia y de la región de las islas Baleares.
Introduction
The Mediterranean Sea is a semi-enclosed sea (Figure 1) that receives inflowing of Atlantic waters through the Strait of Gibraltar (Chic et al., 1997). Evaporation creates a mass deficit in the basin which is compensated by this inflow (Loth and Crepon, 1984). The inflowing waters are lighter than the Mediterranean waters, producing a well defined two layers system. Observations of the vertical structure of water density, low frequency atmospheric fluctuations, and the application of an analytical model over the Ligurian Sea, show the importance of the barotropic and first baroclinic modes (Gasparini and Manzella, 1984). The general circulation of the Western Mediterranean Sea has been widely documented by numerous authors (Ovchinnikov, 1966; Gascard, 1978; Crepon et al., 1982; Bethoux et al., 1982; Philippe and Harang, 1982; Heburn, 1995; Beckers et al., 1997, among others). Millot (1987; 1991; 1999) and Send et al. (1999) presented an accurate description of the circulation in the Western Mediterranean Sea from data and most of the available papers, and assembled them in schematic charts.
Several hypothesis, summarized by Vakalyuk et al. (1986), were formulated trying to explain the origin of the cyclonic and anticyclonic eddies in the Western Mediterranean. The first one assumes that the cyclogenesis in the Ligurian Sea is induced by specific conditions of large-scale atmospheric circulation over the Western Europe and Eastern part of the Atlantic Ocean. The second hypothesis assumes that the origin and development of this cyclonic feature depend on specific hydrological conditions in the surface layer of the ocean. Perilli and Salusti (1993) show for the Tyrrhenian Sea, a constant--stratification flow, this is in agreement with the theoretical idea of a one layer flowing in this sea.
Heburn (1990), using results of several numerical models (one-active layer, reducing gravity model forced by winds, inflow/outflow mass, and/or density variations), and satellite observations shows that the Mediterranean Sea has complex circulation patterns which are time-dependent. On the other hand, historical satellite images, aircraft, and in situ data, have shown two anticyclonic gyres: one at the western part of the Alboran Sea and the other at its eastern part. These are major oceanic features of this sea (Heburn and La Violette, 1990).
On the large scale, an evaluation of the associated surface circulation in the Gulf of Lion made by Johns et al. (1992) confirms the presence of a prominent anticyclonic eddy in the southwest part of the gulf. On the Balearic sides, two fronts follow the continental shelf break. This mesoscale phenomena is proposed in terms of cyclonic eddies generated by some kind of instability mechanism in the two frontal systems by Font et al. (1988).
It appears from all the large international programs (WMCE, POEM, and the Gibraltar Experiment) that the main control of the physical character of the Western Mediterranean Sea is the continental climate and their seasonal variability (La Violette, 1995).
The barotropic response of the Western Mediterranean Sea is always associated to the atmospheric pressure (Lacombe, 1961; Crepon, 1965; Garrett, 1983; Candela and Lozano, 1995; Puig et al., 2000). On the other hand, strong baroclinic processes can be observed in this basin (e.g. complex patterns related to eddies, frontal meanders and filaments, deep water formation, etc.). For this reason barotropic processes induced only by the inflow through the Strait of Gibraltar have not been studied intensively. In this study, in order to understand better the barotropic dynamics in the Western Mediterranean Sea, a very simple barotropic depth-integrated model, forced by the flow in the upper layer, through the Strait of Gibraltar and the Strait of Sicily is considered.
Basic Equations
The barotropic mode can be simulated using a numerical model vertically integrated in a flat tangent plane to the earth surface ([beta]-plane).This model uses momentum and continuity equations for a...
NOTE: All illustrations and photos
have been removed from this article.
Looking for additional articles?
Search our database of over 3 million articles.
Looking for more in-depth information on this industry?
Search our complete database of Industry & Market reports by text, subject, publication
name or publication date.
About Goliath
Whether you're looking for sales prospects, competitive information, company
analysis or best practices in managing your organization,
Goliath can help you meet your business needs.
Our extensive business information databases empower business
professionals with both the breadth and depth of credible,
authoritative information they need to support their business
goals. Whether it be strategic planning, sales prospecting,
company research or defining management best practices -
Goliath is your leading source for accurate information.
|
