Baroclinic circulation in the Gulf of Patras (Greece)

Three-dimensional numerical simulations, performed using the MIKE 3 FM (HD) code, have been used to study the hydrodynamic circulation of the Gulf of Patras. Simulated salient features of the summer-time simulated circulation include strong tidal currents in the main body of the Gulf, which further accelerate through the Rio-Antirio straits where an internal wave is generated, upwellings in the Gulf of Patras and Nafpaktos Bay, and the development of a central cyclonic gyre. The location of the simulated summer-time upwellings is in agreement with information reported in the literature, and the conditions under which they occur have been determined qualitatively. Winter-time simulations have also revealed upwellings at the same locations and under the same wind and tide conditions (with one exception); these have not been reported in the literature presumably because of their lack of temperature-signature. The presence of summer-time stratification produces a phase lag for the exchange flowrate at the Rio-Antirio straits, compared to the winter-time regime, due to the generation of internal waves, but has a minor effect on its magnitude. The numerical simulations have been validated against satellite infrared images and field data, which qualitatively confirm the reproduced results.