ASSESSING THE TREATMENT OF RADIATION IN CLIMATE MODELS

The treatment of radiation in contemporary climate models is considera bly more complex than that used by Arrhenius. While this offers many m ore possibilities for investigations than were available a century ago , the very complexity of the models now in use demands that they be su bjected to wide-ranging evaluation. This paper discusses some of the w ays in which the radiation codes and models may now be compared with o bservations and some of the issues which those comparisons have raised . The opportunities for studies of the clear-sky greenhouse effect off ered by data from the re-analysis project performed at the European Ce ntre for Medium-range Weather Forecasts are highlighted, and some prel iminary results from comparisons with the Hadley Centre Climate Model are shown.