SCENGEN is a software tool that enables the user to exploit results from both simple and global climate model experiments, combined with observed global and regional climatologies, to construct a range of geographically- explicit future climate change scenarios for the world. The scientific rationale for the approach adopted in SCENGEN has been developed over a number of years by the Climatic Research Unit, working with colleagues around the world. The software framework allows the user to explore the consequences for future climate of adopting different assumptions about climate system parameters and emissions scenarios. The software also allows the user to select and apply the results from a range of diffrent General Circulation Model (GCM) experiments. The effects of sulphate aerosols on future climate are included in the software, and the user may explore these effects at both the global-mean and regional (spatial pattern) scales.
The 'driver' for SCENGEN is the global-mean temperature anomaly produced by the linked software program MAGICC. MAGICC was used to produce the global-mean temperature and sea-level rise projections given in the IPCC Working Group I Second Assessment Report (IPCC, 1996). The present softwre therefore gives results entiely consistent with the SAR. The concept used by SCENGEN can be summarised as follows:
These first two stages are accomplished by MAGICC.
Steps 3 to 5 will define a global or regional climate change scenario forced by greenhouse gas emissions only. Step 6 will create an actual future climatology for this scenario by using a 1961-90 climatology to define current regional climate patterns upon which the future climate change is superimposed.
Steps 7 to 9 will create a global or regional climate change scenario using both greenhouse gas and aerosol forced patterns of climate change, with Step 10 creating a future actual climatology for this scenario.
IPCC (1996) Climate change 1995: the science of climate change (eds.) Houghton,J.T., Meiro Filho,L.G., Callendar,B.A., Harris,N., Kattenburg,A. and Maskell,K. Cambridge University Press, Cambridge, UK, 572pp.
SCENGEN scientific developers, Mike Hulme, Tom Wigley and Olga Brown, January 2000