Institute of Computational Mathematics and Mathematical Geophysics

Тезисы докладов

Пленарные доклады

The World Ocean contains numerous semi-enclosed seas; for example, Black Sea, Mediterranean Sea, Baltic Sea, Red Sea, Persian Gulf, White Sea, Sea of Okhotsk, Sea of Japan (alias East Sea), Gulf of Mexico, Caribbean Sea, and Gulf of California (alias Sea of Cortez), to name several. From this enumeration, it can be recognized that semi-enclosed seas have a great variety of sizes, orientations, and climatic regimes. Of course, their most common feature is that their connection to the open ocean is restricted to one or more port (i.e., channels or straits). These ports are also generally restricted in depth (by a “sill”) relative to the adjoining open ocean and semi-enclosed sea. Due to their large size relative to the baroclinic Rossby radius of deformation, and their substantial depth, another shared feature is that they exhibit some of the features of the general ocean circulation. On the other hand, due to their small size relative to the global ocean, it has been more feasible to model numerically and observe synoptically their circulation with the high resolution needed to represent key processes than it has been for the global ocean.

The circulation of semi-enclosed seas is under the combined influence of variable bottom topography, density stratification, and the Earth’s rotation. To varying degrees, such circulation is driven by external forces; such as, atmospheric forcing (winds, pressure, heating/cooling, evaporation/precipitation, freezing/melting) on time and space scales ranging from mesoscale (e.g., coastal orographic winds and coastal sea/landbreezes), synoptic scale (e.g., tropical and extratropical cyclone passages and wintertime cold air outbreaks), seasonal scale (e.g., monsoons and modulation, or even reversals, of alongshore winds), interannual variability (e.g., el Nino/la Nina events), and longer-term climatic regime shifts. Other external forces include tides, river discharges and distributed (i.e., non-point source) runoff, and, very importantly, the inflow/outflow from/to the open ocean for the one-port cases, or the throughflow of the open ocean for the multiple-port cases. In addition to external influences, semi-enclosed seas have intrinsic variability induced by dynamical instabilities of the slowly-varying mean circulation, which is manifested as meandering jets, fronts, and mesoscale eddies. Because waters below the sill depth cannot be easily exchanged with the open ocean, there is dynamical interest in mechanisms for renewal or ventilation of the deeper waters of semi-enclosed seas. For example, in some of these seas, wintertime convection extends to intermediate or bottom depths due to surface cooling and/or evaporation or due to ice formation and brine rejection, which accounts for one limb of their overturning regime.

The approach taken here is to present several examples of numerical simulations and synoptic observations from semi-enclosed seas to illustrate the controlling dynamics, the state-of-the-science, and the open questions requiring further numerical analysis and observational validation. Examples are taken from several semi-enclosed seas, including the Intra-Americas Sea (i.e., the combined Caribbean Sea, Gulf of Mexico, and Straits of Florida), Japan (East) Sea, and Prince William Sound (Alaska), which represents a broad range of sizes, configurations, locations, and climatic regimes.

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    Дата последней модификации: 06-Jul-2012 (11:52:46)