Final results of the model inter-comparison of veryhigh-resolution simulations with numerical weatherprediction models for eight urban air pollution episodes infour European cities

摘要

Meteorological conditions during eight air pollution episodes weresimulated in the target cities Helsinki, Oslo, Bologna and Valenciawith varying participation of three HIRLAM versions, Lokalmodell/LAMI, MM5 and RAMS. The models were used with their oper-ational parameterisations but tested for increased resolution ofup to 1 km by multiple nesting. The meteorologically extreme winterepisodes in Helsinki, Oslo and Bologna are dominated by ground-based inversions in very stable stratification which are poorlysimulated, and the causes investigated. For the less meteorologicallyextreme summer photochemical episodes in Valencia and Bologna,the models perform better and succeed in simulating the dominatingmesoscale circulations. In Bologna, the variable border between anApennine mountain-valley breeze and a larger Po valley circulationreduces predictability.