Intercomparison of Meteorological Models Applied to the Athens Area and the Effect on photochemical Pollutant Predictions

View More View Less
  • a Ecole Polytechnique Federale of Lausanne, Lausanne, Switzerland
  • | b Carnegie Mellon University, Pittsburgh, Pennsylvania
© Get Permissions Rent on DeepDyve
Restricted access

Abstract

In this study, four different meteorological models, one diagnostic and three prognostic, are used to develop meteorological inputs for a photochemical model, as applied to the peninsula of Athens, Greece. The comparison of meteorological models results pointed out significant differences in the calculated wind fields, mainly during the night period. These differences are linked to specific aspects of the models, such as model vertical resolution, hydrostatic versus nonhydrostatic formulation, and numerical diffusion. During the day hours, models produce quite similar wind fields, which agree correctly with the available observations related to the Athens center area. Using the different wind fields as input to a photochemical air quality model led to similar urban ozone levels in the Athens area. Outside of the city, the different wind fields transport the urban plume in different directions in a range of 50°. The more primary pollutants, for example CO and NO2 concentrations, varied significantly due to the different wind velocities predicted by meteorological models. The effect of the atmospheric deposition can be near zero or can go up to 25% for ozone and to 45% for NO2. The determination of the most appropriate wind field to be used for the photochemical modeling would have required a more comprehensive set of observed data. Therefore, when data are scarce, it may be recommended to use different wind field modeling techniques to assess the sensitivity and the robustness of the predicted concentrations.

Abstract

In this study, four different meteorological models, one diagnostic and three prognostic, are used to develop meteorological inputs for a photochemical model, as applied to the peninsula of Athens, Greece. The comparison of meteorological models results pointed out significant differences in the calculated wind fields, mainly during the night period. These differences are linked to specific aspects of the models, such as model vertical resolution, hydrostatic versus nonhydrostatic formulation, and numerical diffusion. During the day hours, models produce quite similar wind fields, which agree correctly with the available observations related to the Athens center area. Using the different wind fields as input to a photochemical air quality model led to similar urban ozone levels in the Athens area. Outside of the city, the different wind fields transport the urban plume in different directions in a range of 50°. The more primary pollutants, for example CO and NO2 concentrations, varied significantly due to the different wind velocities predicted by meteorological models. The effect of the atmospheric deposition can be near zero or can go up to 25% for ozone and to 45% for NO2. The determination of the most appropriate wind field to be used for the photochemical modeling would have required a more comprehensive set of observed data. Therefore, when data are scarce, it may be recommended to use different wind field modeling techniques to assess the sensitivity and the robustness of the predicted concentrations.

Save