Chemistry As A Boxmodel Application
Module Efficiently Calculating the Chemistry of the Atmosphere

What is MECCA?

MECCA is an atmospheric chemistry module that contains a comprehensive chemical mechanism with tropospheric and stratospheric chemistry of both the gas and the aqueous phase. In addition to the basic HOx, NOx, and methane chemistry, it also includes non-methane hydrocarbons (NMHCs), halogens (Cl, Br, I), sulfur (S), and mercury (Hg) chemistry. A complete list of chemical reactions, including rate coefficients and full references, is available in pdf format here. For the numerical integration, MECCA uses the KPP software.

What is CAABA?

To apply the MECCA chemistry to atmospheric conditions, MECCA must be connected to a base model via the MESSy interface. This base model can be a complex, 3-dimensional model but it can also be a simple box model. CAABA is such a box model, simulating the atmospheric environment in which the MECCA chemistry takes place. It is possible to choose from several scenarios, e.g. the marine boundary layer, the free troposphere, the stratosphere, or even a smog chamber in a laboratory. Further scenarios can be added easily.


When referring to the combination of the CAABA box model with MECCA chemistry, the term "CAABA/MECCA" is used. Several model description papers about the box model and its components have been published in a special issue in GMD. A user manual in pdf format is available here. The current stable and official code version is 4.0. Further information about the CAABA/MECCA box model is available here.

CAABA/MECCA can be run inside a virtual machine. For more information about this option, please contact Rolf Sander.

Rolf Sander This document was last changed: 31 Aug 2022