Auswirkungen anthropogener Einfluesse auf die atmosphaerische Zirkulation Abschlussbericht

In this research project, different runs of the Hamburg climate model ECHAM (some of them coupled to an ocean model) were used in order to estimate the effects of rising greenhouse gas concentrations on atmospheric circulation. A prejudice for the reliability of model predictions of a future climate is the correct representation of the circulation features for present climate conditions. As a consequence, it is investigated - if circulation features in model runs for the present climate agree with observations - which changes to circulation are introduced by rising atmospheric greenhouse gas concentration. Among the circulation features considered are the atmospheric energy cycle, baroclinic wave activity within the mid-latitude stormtracks and the related cyclone tracks, baroclinic instability and the organization patterns of the low frequency variability. The representation of the present-day climate was clearly improved in the course of model development at the MPI and DKRZ in Hamburg. It is remarkable, that local deviations from reality found for the time averages of different parameters generally turn out to be physically consistent with each other. Such consistency is also found for their interannual variability, which, as a rule, is smaller than observed. There is a clear anthropogenic signal for each parameters considered. (orig./KW)SIGLEAvailable from TIB Hannover: F95B1689+a / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman