[ Derived from parent entry - See data hierarchy tab ] Up to 1985 the concentration followswere taken from observation (Schoenwiese et al., 1990) and for the following years the IPCC scenario A (Business as Usual, Houghton et al., 1990) was applied. In addition the direct effect of suphate aerosols was simulated. The aerosol data were calculated using the MOGUNTIA sulphur model (Lange and Rhode, 1991). The Sulphate emissions were taken from historical data and from projected future emissions from the IPCC 1992 scenario A. The experiments 17124 and 17126 differ only through the introduction of a small perturbation (at least an order of magnitude smaller than the uncertainties in the aerosol forcing) into the aerosol fields of one of the runs. The models ECHAM3 and LSG are described in the DKRZ reports No.6 and No.2, respectively.