A Real-Time Operational Forecast Model for Meteorology and Air Quality During Peak Air Pollution Episodes in Oslo, Norway

A real-time operational forecast model for meteorology and air quality for Oslo, Norway is presented. The model systemconsists of an operational meteorological forecasts modeland an air quality model. A non-hydrostatic model operatedon two different domains with 1 and 3 km horizontalresolution is nested within the routine meteorologicalforecast model, which is run for North West Europe with 10 kmhorizontal resolution. The meteorological data are applied to an air quality model of Oslo with a 1 km grid and sub-grid treatment of line and point sources. Resultsfrom 22 days during the winter season 1999–2000 arepresented and discussed. Prediction of wind speed anddirections and relative humidity are clearly improved byincreasing the horizontal resolution of the meteorologicalmodel. Temperature inversion strengths are howeverconsiderably overestimated. The predictions of PM10corresponds best with measurements on winter days with wetor frozen surfaces in the city. On dry days, especiallyduring spring time with a large deposit of accumulated duston the roadside, the model under predicts the PM10concentrations considerably. It is in particularrecommended to improve the description of the PM10source strength in order to enhance the precision in theair quality forecasts.