Modelling the effect of wind on average circulation and long-term pollutant dispersion in the Gulf of Trieste

Abstract

       Two methods for the evaluation of the effect of wind for long-term prognostic hydrodynamic (HD) and advection-dispersion (AD) simulations are presented and their efficiency and applicabil­ity is studied for the case of the Gulf of Trieste. Both methods are applicable only in cases of homogenous (spatially constant) wind fields. They also both apply common wind roses as the only input, which ensures easy and fast preparation of wind data.

       The VERANDA method employs a stochastic approach and is designed for use in non-stationary HD and AD models, while the deterministic VECTRA method is used in both stationary and non-stationary models. Both methods were used to create synthetic time series of wind data which were the input for HD and AD models. Results of simulations using these synthetic winds are com­pared with results of a reference simulation where wind input was a 1-year measured time series. Comparisons are performed on the basis of concentration fields, velocity fields and point values of concentration and velocity. An acceptable accuracy is found for both methods if they are used in accordance with adopted assumptions.