Numerical forecasting of ozone at the surface

Abstract

Publisher Summary Exposure to elevated concentrations of ozone gives rise to a health risk for the human population and impairs agricultural productivity. National air quality standards, directives, or guidelines have been introduced in many countries around the world. The chapter describes a coupled chemistry–transport model (CTM) and shows the way in which an ozone forecast can be made when a modern numerical weather prediction model is run in combination with a state of the art chemistry model. The general approach used in the model is similar to that used in several other three dimensional models developed in the past. The mesoscale chemical transport (MCT) model is closely coupled to a numerical weather prediction (NWP) model with an advanced treatment of cloud physics and precipitation processes. This allows a detailed parameterization of convective transport and the calculation of photolysis rates in cloudy conditions to be made. The coupled NWP and chemistry model can be run with sufficient computational efficiency to be used in a forecast mode, provided that an appropriate weather analysis is available to initialize the numerical weather prediction model.