engleski

Boundary layer height determination under summertime anticyclonic weather conditions over the coastal area of Rijeka, Croatia

The atmospheric boundary layer height is a fundamental parameter characterising the structure of the lower troposphere. The determination of this parameter is important in applications that range from meteorological modelling and forecasting to dispersion problems of atmospheric pollutants. Since substances emitted into the atmospheric boundary layer are dispersed horizontally and vertically through the action of turbulence, they are well-mixed over this layer that is widely called "mixing layer". Furthermore, the complexity of the geographical characteristics of the coastal areas and the land-use plays an important role in the determination of this layer. The aim of the present study is to evaluate the mixing layer height and to analyze its variability in relation to underlying topography and land-use. Rijeka, a region with complex topography and several islands in its surroundings, offers the opportunity to examine these relationships. The non-hydrostatic mesoscale model MEMO has been used in order to calculate the boundary layer mixing height over the Greater Rijeka Area, under summertime anticyclonic weather conditions. In this study, three multi-day periods characterised by stagnant meteorological conditions were selected and proved capable of simulating mesoscale wind flow reasonably well. Further investigation related to the choice of some of the input model parameters as well as to their origin and way of calculation (e.g. satellite data) was carried out for improving the model performance. The evaluation of the results of the different parameterization is discussed and was proved useful for the more accurate determination of the mixing layer height.

boundary layer height; summertime; anticyclonic; mesoscale model; non-hydrostatic; Northern Adriatic

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