WIT Press

Sensitivity Tests Of MM5 Modelling System Over A Coastal Region In Portugal


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WIT Press


A. Carvalho, J. Ferreira, J. L. Arreola, A. C. Carvalho, A. I. Miranda, S. Alonso & C. Borrego


The west coast of Iberian Peninsula, surrounded by the Atlantic Ocean, is characterized by complex topography and some favourable synoptical situations, which imply the occurrence of mesoscale circulations, namely sea/land breezes and anabatic and katabatic flows. Air quality standards are strongly influenced by these patterns leading to the enhancement of photochemical pollutants levels. In order to evaluate air quality levels in Aveiro, study region, a field campaign was carried out from 24th June to 2nd July of 2001, which covered the highest ozone (O3) episode noticed in the region during the year of 2001. To correctly assess air quality over Aveiro region not only measurements are required but also the application of an integrated system of meteorological and photochemical models. Aiming to achieve more satisfactory air quality results both models must be evaluated over the interested region. Accordingly, meteorological model evaluation should be performed firstly. In this scope, the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Meteorology Model (NM.5) was applied using its nesting capabilities. Sensitivity analyses were also done in order to better understand how grid size influences model results and its behaviour under distinct meteorological situations. MM5 modelling system was applied to two 48 hours periods during summer 2001, in the North part of Portugal. MM5 application to this region presented a good skill when simulating anticyclone conditions. This study should be considered as pilot, because other