Boundary layer dynamics in an urban coastal environment under sea breeze conditions

A three-dimensional, higher-order turbulence closure model is applied to simulate the boundary layer dynamics in Attica peninsula, where the city of Athens is located. All model equations are transformed to a terrain influenced coordinate system, which enables studies of flow over complex terrain. Major characteristics of the sea breeze circulation including vertical extension and intensity as well as the growth rate of the thermal internal boundary layer are identified and discussed. Model predictions agree fairly well with measured profiles at one location and measured surface winds in the center of Athens. In addition to the basic simulations, a series of sensitivity tests has been performed in order to evaluate the relative importance of the various input parameters. It was found that some parameters (topography, the amplitude; of the diurnal variation of the temperature over the land) have relatively larger impact on the development of sea breeze circulation over the Athens basin than others. The sea breeze circulation developing at the east side of the Attica peninsula is particularly sensitive to the input geostrophic wind.