A nested circulation model for the North Aegean Sea

[摘要] A multi-nested approach has been employed for numerical simulations in thenorthern part of the Aegean Sea in the framework of the MFSTEP(Mediterranean Forecast System: Toward Environmental Predictions) project.The high resolution (~1.6 km) hydrodynamic model of the North AegeanSea (NAS) has been nested within a coarser model of the EasternMediterranean (resolution ~3.6 km) which is also nested within a basinscale model for the Mediterranean Sea (resolution of ~7 km). The highresolution of the NAS model allows the representation of topographic detailsthat have never been reproduced in modelling studies of the region. Suchdetails can enhance the simulation of coastal features, but can alsoinfluence basin-scale processes, such as the pathways of waters of Black Seaorigin inflowing at the Dardanelles Straits and bifurcating through islandpassages.

We employ comparisons of the North Aegean and Eastern Mediterranean modelsin terms of computed flow fields and distribution of hydrodynamicproperties, to evaluate the nesting procedure, the initializationrequirements and the ability of a nested model to perform reliable shortterm simulations that employ high resolution atmospheric forcing, wheninitialized from a coarser OGCM.

We show that the topographic details of the high resolution, nested NASmodel affect the distribution of the Dardanelles plume and the evolution ofcoastal currents, while the imposed high frequency, high resolutionatmospheric forcing allows for the formation of an overall energetic flowfield after a few days of spin-up period. Increased resolution and smallercoastal depth in the NAS simulations influence the flow through islandpassages and straits. A longer initialization procedure results in theestablishment of stronger currents and better-developed buoyant plumes.

[学科分类] 海洋学与技术