Roeckner95 Roeckner, E., 1995: AMIP-experiments with the new Max Planck Institute Model ECHAM4. Abstracts of the First International AMIP Scientific Conference, Monterey, California, 95.

Two 15-year simulations have been performed using observed SSTs (1979-1993) with the latest version of the MPI model (ECHAM4). The model differs from the previous AMIP version (ECHAM3) in several aspects: The transport of humidity and cloud water is calculated with a semi-Lagrangian technique. A new radiation scheme is employed (ECMWF code) with revised water vapor continuum and cloud optical properties. The code has beed extended to include additional greenhouse gases such as methane, nitrous oxide and CFSs. The detrained fraction of the convective cloud water is used as a source term in the cloud water transport equation, and the closure for deep convection is based on convective available energy instead of moisture convergence, used in the previous scheme. Moreover, new datasets for land surface properties (albedo, vegetation types, leaf area index, field capacity etc) have been compiled for the model.

The simulated climate obtained with ECHAM4 will be compared with that of the previous version and observations, with particular emphasis on the surface climate, the radiation budget and the hydrological cycle.