The Chemistry of the global Atmosphere represented in Lagrangian and Eulerian Simulations

Abstract

Simulating the chemistry of the Earth’s atmosphere is a challenging task, both scientifically and computationally because it combines many disciplines and a large range of space and time scales. The atmospheric chemistry general circulation model ECHAM5/MESSy (http://www.messy-interface.org) combines two complementary approaches which can be used simultaneously within a consistent framework: The Eulerian formulation, where the processes are calculated in stationary grid-boxes, and the Lagrangian formulation where the processes are calculated along dynamical trajectories. The former approach has been proven to be successful at sufficiently high horizontal and vertical resolutions. The latter approach, which holds great promise for the quantification of transport fluxes of trace species and important precursors between different regions of the globe, is presently in development. It is expected that the Lagrangian approach will produce many more details and much higher accuracy with less computational effort (i.e., at a reduced resolution) compared to the corresponding Eulerian simulation. The infrastructure and technologies provided by DEISA, in particular the available computing time, the storage capacities and the data transfer systems, will provide the ideal environment to test the convergence of the Eulerian results (with increasing grid resolution), being a prerequisite for the evaluation of the newly developed Lagrangian approach.