A NUMERICAL-MODEL FOR WIND-FIELD AND POLLUTANT CONCENTRATION CALCULATIONS OVER COMPLEX TERRAIN - APPLICATION TO ATHENS, GREECE

A non-hydrostatic, three-dimensional, prognostic, mesoscale model is d eveloped for the calculation of the flow field and pollutant concentra tions over complex terrain. The model solves numerically in an implici t, time-dependent manner the full Reynolds equations, in Cartesian, co llocated grid arrangement. The differential equations are discretized by the finite volume method and solved iteratively with the SIMPLE alg orithm. Turbulence closure is obtained by the two-equation (k-epsilon) turbulence model. A technique of partially covered cells is introduce d for an accurate representation of complex terrain features. The grea ter area of Athens, Greece, which combines significant topographic and sea-breeze aerodynamic complexities, is chosen for the model performa nce evaluation. The results reproduce reasonably well the diurnal vari ation of the wind and pollutant concentration fields, and the comparis on with available observations is satisfactory. (C) 1998 Elsevier Scie nce B.V. All rights reserved.