Short-Term Forecast of the Carbon Monoxide Concentration Over the Moscow Region by COSMO-ART

A short-term forecast of the city “chemical weather” requires real daily data on pollutant emissions. For operational daily forecasts of pollutant concentrations, usually long-term emission averages are used which may differ significantly from real values for a certain day, especially in big cities with intense and variable human activities. The online coupled atmospheric chemical transport model COSMO-ART was implemented for the Moscow region, Russia. A method for calculation of pollutant emissions for short-term forecasting was suggested. In this method, “actual” emissions for a certain day are obtained from measurements of air pollutant concentrations. It is assumed that the pollutant concentration reflects the spatially averaged intensity of emission sources. We used the observational data of pollutant concentrations from the network of the State Ecological Monitoring System of Moscow City. In order to get a more homogeneous field of data, “virtual” stations (so-called "bogus data") were added within the areas not covered with observations. The proposed method allows a transformation of the hourly measurements of air pollutant concentration to emission values just after the measurements are completed. We showed the application of this method for carbon monoxide. Verification of COSMO-ART results demonstrates that the forecasts based on emissions calculated by the new method are better than the ones based on climate mean emissions. The approach suggested in the study provides a possibility to issue more detailed operational short-term forecasts of pollutant concentrations for megacities depending on the real air pollution of the previous day. The main limitation of this methodology is that it can be applied to the chemical species that have longer chemical life-time compared to the frequency of concentration measurements.