Response of the Météo-France climate model to changes in CO2 and sea surface temperature

Abstract

The climate response to an increase in carbon dioxide and sea surface temperatures is examined using the Météo-France climate model. This model has a high vertical resolution in the stratosphere and predicts the evolution of the ozone mixing ratio. This quantity is fully interactive with radiation and photochemical production and loss rates are accounted for. Results from a 5-year control run indicate a reasonable agreement with observed climatologies. A 5-year simulation is performed with a doubled CO2 concentration using, as lower boundary conditions, mean surface temperatures anomalies and sea ice limits predicted for the years 56-65 of a 100-year transient simulation performed at Hamburg with a global coupled atmosphere-ocean model. The perturbed simulation produces a global mean surface air warming of 1.4 K and an increase in global mean precipitation rate of 4%. Outside the high latitudes in the Northern Hemisphere, the model simulates a strong cooling in the stratosphere reaching 10 K near the stratopause. Temperature increases are noticed in the lower polar stratosphere of the Northern Hemisphere caused by an intensification in the frequency of sudden warmings in the perturbed simulation. The low and mid-latitude stratospheric cooling leads to an ozone column enhancement of about 5%. Other features present in similar studies are exhibited in the troposphere such as the stronger surface warming over polar regions of the Northern Hemisphere, the summer time soil moisture drying in mid-latitudes and the increase in high convective cloudiness in tropical regions. © 1994 Springer-Verlag.