A three-dimensional model for combined tropospheric and stratospheric sulfur cycle studies

We are developing a three-dimensional atmospheric photochemical transport model, named IMPACT, which contains both a prognostic troposphere and stratosphere. This model is being used to study the influence of natural and anthropogenic activities on the distribution of species important to the sulfur cycle on global and regional scales. Our distinctive chemical mechanism includes species and reactions important to both the troposphere and stratosphere. Assimilated meteorological fields drive the model, which allows direct model comparison to observed data, including specific campaigns such as SONEX, PEM and UARS. IMPACT is fully parallelized and implemented on a wide range of computer platforms (both parallel and non-parallel) using two-dimensional domain decomposition and message passing. In this paper we will present preliminary studies focused on the processes governing the sulfur cycle and resulting aerosol distributions.