The Chemical Lagrangian Model of the Stratosphere (CLaMS)

Trace substances in the atmosphere are influenced by transport processes and chemical reactions. Both transport processes and chemical reactions occur on various time scales. Moreover, the impact of atmospheric transport barriers on transport in the atmosphere must also be taken into consideration. Examples of transport barriers are the tropopause, and fast-flowing air currents (“jet streams”). In order to quantitatively describe trace substances, all these processes must be accurately represented in a numerical model. This requires very detailed numerical models with a high spatial resolution. Results from these model simulations can then be compared with  high-quality comprehensive atmospheric data sets and also with the results of global climate models.

It is neither possible nor useful to distinguish between model studies that improve the prognostic value of the models and those that are aimed at the evaluation of fields measurements and other observations. CLaMS is used to analyse high-resolution global satellite data as well as measurements from high-altitude aircraft and balloons. The model can be applied to the extratropical tropopause, the tropical tropopause region, the Asian monsoon, and the polar vortex.