A Spatio-Temporal Model for Mexico City Ozone Levels

Gabriel Huerta, Bruno Sansó, Jonathan R. Stroud

University of New Mexico, UC-Santa Cruz, University of Pennsylvania

We consider hourly readings of ozone concentrations over Mexico City and propose a model for spatial as well as temporal interpolation and prediction. The model is based on regressing the observed readings on air temperature. Two harmonic components are added to account for the main periodicities that ozone presents during a given day and that are not explained by the temperature covariate. The model incorporates spatial covariance structure for the observations and the parameters that define the harmonic components. Using the dynamic linear model framework, we show how to compute smoothed means and predictive values for ozone. We illustrate the methodology on data from September, 1997.

The manuscript is available in PDF format.