Abstract

GARFIAS VAZQUEZ, Margarita; AUDRY SANCHEZ, Javier  and  GARFIAS Y AYALA, Francisco Javier. Tropospheric Ozone Prediction in Mexico City. J. Mex. Chem. Soc [online]. 2005, vol.49, n.1, pp.2-9. ISSN 1870-249X.

Two techniques are applied to forecast time series for the hourly ozone measured at Pedregal's recording station of the Automatic Network for Environmental Monitoring (RAMA for its acronym in Spanish) located in the metropolitan area of Mexico City. The techniques have been widely applied since last century: the autoregressive (AR) and the method of delays in an embedded space. The predicted values by the autoregressive method are somewhat less precise than those forecasted by the embedded space method, as presented below. It is intended to predict the maximum ozone daily concentration in advance to be able to alert the citizenship or for taking appropriate control measures. In this presentation, the models have as main limitation to be based only on the ozone time series; more robust models should take into consideration meteorological variables to increase precision. If it is roughly considered only the series formed by the hourly ozone series from January to May 1999; the series of daily ozone maxima have an standard deviation of around 0.05 ppm of ozone. In the most precise -the embedded space method- shown at the end of the article, the error standard deviation between predicted and real maximum daily ozone data is around 0.027 ppm of ozone, which shortens the gap, considering the total of the ozone maximum as a normal distribution.

Keywords : Ozone measurements; Mexico City; autoregresive method; embedded space method.

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