Comparison of measured and forecast–based vertical ozone profiles in the lowest 3 km of the atmosphere over the Eastern US during summer 2007

In this paper we compare observed vertical profiles of ozone (O3) and meteorological parameters below 3 km with those based on an air quality forecast model at 14 locations across the eastern US during the summer of 2007. Segregating the vertical profiles into nighttime (0100 to 0500 EST), morning (0600 to 1200 EST), and afternoon (1300 to 1700 EST), the average observed and predicted O3 profile patterns showed good agreement above 600 m with < 15 ppb mean bias, but the model failed to capture the observed range of concentrations in the lower 600 m of the atmosphere. This lack of agreement in the lower levels suggests the need for further assessment of the input data (e.g. emissions and meteorology) and model setup, including the use of higher vertical resolution below 600 m, in order to better understand and improve the chemical and dynamical processes employed in the modeling system.