Fig. 17: Mean sea level pressure (MSLP) response in SSP370 scenario simulations (2071–2100) compared to historical simulations (1985–2014). For both the scenario and the historical simulations the 5 member ensemble means have been computed. (a) DJF, (b) MAM, (c) JJA, (d) SON.
Fig. 18 shows the zonal mean temperature and zonal mean zonal wind response to scenario forcing. The typical global warming signature with pronounced upper tropospheric tropical warming and near-surface polar warming occurs in AWI-CM as expected. The strongest warming in excess of 6 °C occurs in the Arctic boundary layer north of 70°N - known as Arctic Amplification. The upper tropospheric tropical warming amounts to 4 to 6 °C while the Antarctic warming is limited to around 4 °C. Strongest zonal mean zonal wind changes occur in the stratosphere around 100 hPa with increases in the westerly wind speed by around 5 m/s in 30 to 40°N and in 30 to 50°S. Around 60°S there are increases in the westerly wind speed by around 1 to 2 m/s throughout the troposphere. This pattern is very similar to the multi-model mean of CMIP5 (IPCC, 2013, chapter 12, their Fig. 12.19).
(a) (b)