Both the troposphere and stratosphere are affected by natural and anthropogenic emissionsof trace species. These species, in turn, react, to form a large suite of products, including chemically and radiatively important gases such as ozone (O3) and the hydroxyl radical (OH). Because so few measurements exist, models are useful to both understand the current state of the atmosphere and predict how
that may change if emissions change.
In the past, large scale chemistry-transport-deposition models have often been "driven" by meteorology from general circulation models, that is, "climatologically averaged" meteorology. Results from these models are usually compared todata averaged over a number of years. We have developed a global atmospheric model that uses actual data assimilated meteorological fields. This allows us to simulate actual past periods of times. The model also includes both a prognostic stratosphere and troposphere, allowing us to treat a number of key regions, including near the tropopause.
In this work, we show results of a present day simulation, with emphasis on the North American continent. We compare the model results with observations appropriate for the same time period. The combination of both observations and model results allows us to understand how well the model can recreate historic events, and quantify uncertainties in predicting future scenarios. The model also is useful in addressing the characteristics of both inflow and outflow air for the North American continent.
Symposium on Interdisciplinary Issues in Atmospheric Chemistry