Lagrangian Transport in a Chemistry Climate Model: Methods and Applications

Abstract

The global ECHAM5/MESSy Atmospheric Chemistry (EMAC) Model is equipped with the Lagrangian transport submodel ATTILA and further corresponding Lagrangian process and diagnostic submodels. The long-term objective of this development is a full representation of atmospheric chemistry related processes in the Lagrangian frame of reference on the global scale. Furthermore, the system serves as a test-bed for new approaches, like the development of a Lagrangian dynamical climate model core. Apart from the common advantages of the Lagrangian approach (mainly mass conservation and nondiffusivity), it provides valuable additional information about spatio-temporal interrelations of atmospheric constituents, which are hardly available from Eulerian modelsW. e present our methods for inter-particle diffusion, large scale and convective transport. The results shown focus on the mass exchange between the stratosphere and the troposphere, on lower stratospheric age of air spectra, and on an inter-comparison of Eulerian and Lagrangian convection and their influence on vertical tracer gradients.