Abstract
The Alfred Wegener Institute Climate Model (AWI-CM) participates for the
first time in the Coupled Model Intercomparison Project (CMIP), CMIP6.
The sea ice-ocean component, FESOM, runs on an unstructured mesh with
horizontal resolutions ranging from 8 to 80 km. FESOM is coupled to the
Max-Planck-Institute atmospheric model ECHAM 6.3 at a horizontal
resolution of about 100 km. Using objective performance indices, it is
shown that AWI-CM performs better than the average of CMIP5 models.
AWI-CM shows an equilibrium climate sensitivity of 3.2°C, which is
similar to the CMIP5 average, and a transient climate response of 2.1°C
which is slightly higher than the CMIP5 average. The negative trend of
Arctic sea ice extent in September over the past 30 years is 20-30%
weaker in our simulations compared to observations. With the strongest
emission scenario, the AMOC decreases by 25% until the end of the
century which is less than the CMIP5 average of 40%. Patterns and even
magnitude of simulated temperature and precipitation changes at the end
of this century compared to present-day climate under the strong
emission scenario SSP585 are similar to the multi-model CMIP5 mean. The
simulations show a 11°C warming north of the Barents Sea and around 2 to
3°C over most parts of the ocean as well as a wetting of the Arctic,
subpolar, tropical and Southern Ocean. Furthermore, in the northern
mid-latitudes in boreal summer and autumn as well as in the southern
mid-latitudes a more zonal atmospheric flow is projected throughout the
year.