UKTR

This experiment was performed in the Hadley Centre in the UK during the winter of 1991/92 using the UK Met.Office's 11-layer high resolution atmospheric GCM, coupled to a 17-layer ocean model. The horizontal resolution of the atmospheric and ocean models is 2.5 deg. latitude by 3.75 deg. longitude. UKTR is a transient experiment in which the year-by-year greenhouse gas forcing is a 1% per annum compounded increase over a 75-year period. It is a "cold-start" experiment, in that no historic forcing was introduced to the model prior to the forcing scenario commencing. The experiment is reported in Gates et al. (1992) and Murphy and Mitchell (1995) and is widely referred to as "UKTR". We acquired the results from this experiment in 1994 through the Climate Impacts LINK Project, based in the Climatic Research Unit. The change fields used in SCENGEN are calculated as the difference in climate between the 10-year means of years 66-75 in the control (323ppmv CO2 concentration) and perturbed (1% per annum CO2 increase) simulations. The global warming by this decade, with respect to the control simulation, was 1.8deg C and the increase in global precipitation was 3.3%, yielding a global precipitation sensitivity of 1.8% per degree Celsius warming. The climate sensitivity of the same atmospheric model, coupled to a mixed-layer ocean, was estimated to be 2.7deg C.

Mean monthly precipitation pattern correlation coefficient = 0.76

References

Gates,W.L., Mitchell,J.F.B., Boer,G.J., Cubasch,U. and Meleshko,V. (1992) Climate modelling, climate prediction and model validation pp.97-134 in 'Climate Change 1992', Cambridge University Press, Cambridge, UK

Murphy,J.M. and Mitchell,J.F.B. (1995) Transient response of the Hadley Centre coupled model to increasing carbon dioxide: Part II J.Climate, 8, 57-80.