Chemical climatology of the middle atmosphere simulated by the NASA Langley Research Center Interactive Modeling Project for Atmospheric Chemistry and Transport (IMPACT) model

The stratospheric chemical characteristics of the NASA Langley Research Center Interactive Modeling Project for Atmospheric Chemistry and Transport model are evaluated. We focus on species relevant to stratospheric ozone including the main constituents of the odd nitrogen and inorganic chlorine families. Model-derived chemical climatologies resulting from 20 years of integrations are compared with observations made primarily by the experiments aboard the Upper Atmosphere Research Satellite. The role of model transport characteristics in determining long-lived tracer distributions is assessed. The model is shown to reproduce observed distributions and seasonal variations of constituents throughout the middle stratosphere. Causes of biases in the upper and lower stratosphere are identified and discussed. In accord with recent observationally based studies, the fundamental coupling between tropospheric wave forcing and stratospheric ozone anomalies is shown to be reproduced by the model.