Effects of uncertainties in meteorological inputs on Urban Airshed Model predictions and ozone control strategies, Atmos

Almraet--Although wcll-rccngnized within the photochemical modeling community, the effect of uncer-tainties in meteorological input on the urban alrshed model (UAM) Output has not been systematically evaluated. Inthis study, the UAM has been applied to investigate he sensitivity of ozone predictions to the choices in wind fields and mixing height profiles for the data-sparse New York metropolitan area. A set of three wind fields, in combination with spatially varying and spatially invafiant mixing heights, isinvesti-gated for the July 1988 ozone episode. In general, mndei-predicted ozone levels were higher under the spatially varying mixing height (SVM) option than under the spatially invariant mixing height (SIM) option. SVM-based UAM simulations provided better agreement between the predicted and measured ozone concentrations than SIM-based UAM simulations. However, from the regulatory standpoint, predicted ozone concentrations based on either of these mixing height options are within the range considered as acceptable. UAM simulations with emission reductions of 75 % NOx and 25 % VOCs (NOx-focnsed) reveal that the improvement i peak ozone levels under the SIM option is larger than that under the SVM option, whereas the emission reduction scenario f 25 % NOx and 75 % VOCs (VOC-focused) yields greater improvement i peak ozone under the SVM option than with the SIM option. Given the strong influence of mixing heights and wind fields on UAM mode] predictions indata-sparse areas, it i