MODELING TROPOSPHERIC OH - A NEW APPROACH

A new fully dynamic model for tropospheric OH has been developed. The model structure is especially designed to comply with the needs of small scale problems and comparison with field data. Using the local character of most measurements providing the boundary conditions to the calculations and the local character of the OH concentration itself, the model is able to simplify the description of transport and deposition processes. Additionally the required initial data set can be reduced thus leading generally to a minimization of the measurement based error of the model results. As a special feature this model can calculate fluxes of atmospheric constituents resulting from emissions and transport which are an input to most models. Combining the photochemical model with budget and sensitivity calculations this system is equipped with testing and self-correction facilities which help to achieve a strong error reduction in tropospheric modelling. First tests simulating dynamic flux-reaction systems have shown that this approach is a very promising new way to model fast tropospheric photochemistry.