Modeling the Impact of Temperature Perturbations on Urban and Regional Ozone Levels in Texas

J. Biswas (India), K. John, and Z.M. Farooqui (USA)


Ozone, climate change, temperature perturbation, photochemical modelling, and near nonattainment area


Atmospheric temperature variations are indicators of climate change in any region. The main purpose of this study was to determine the impact of temperature perturbations on urban and regional ozone concentrations and its distribution in South Texas. A regional photochemical model was employed to study the influence of the increase in temperature on tropospheric ozone for a high ozone episode of September 13-20, 1999. The temperatures were increased uniformly throughout the modeling domain and through the vertical layers by 2, 3, 4, 5 and 6 ºC, respectively, in line with the anticipated enhancements of global temperature as predicted in the most recent Intergovernmental Panel on Climate Change report. These temperature perturbations represented the worst case consequences of extreme climate change in this region and produced significant enhancements in the peak ozone concentrations. The greatest amplification in maximum 8 hr ozone concentrations in South Texas for the 6 ºC temperature perturbation scenario was approximately 8 ppb with pockets of urban areas exhibiting the largest increases on a spatio-temporal basis. In addition, trans-boundary flux from the Houston-Galveston industrialized region played a major role in supplementing the ozone concentrations in the study region under the perturbed temperature scenarios.

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