From the performance indices for the ocean (Table 3), we can conclude that potential temperature is better represented than in CMIP5. However, this is not the case for salinity. Salinity in the Pacific Ocean as well as in the North Atlantic Ocean deviates more from observations compared to the average of CMIP5 models.
While the performance indices give a quick and objective overview of how a model performs compared to other CMIP5 models, it is necessary to carry out more detailed analysis to investigate if typical errors of climate models such as the Southern Ocean warm bias or the cold bias in the North Atlantic subpolar gyre persist. Regarding the errors in potential temperature and salinity, more analysis is provided in section 4.4.
Table 3: Ocean performance indices for years 1985–2014 of the first ensemble member of AWI-CM historical simulations averaged over the two seasons DJF and JJA. The set of CMIP5 models consists of ACCESS 1.3, BCC-CSM 1.1, BNU-ESM, CanESM2, CCSM4, CMCC-CM, CMCC-CMS, CNRM-CM 5.2, CSIRO-Mk 3.6.0, EC-Earth, MPI-ESM-LR, GFDL-CM3, GISS-E2-H, GISS-E2-R, HadGEM2-ES, IPSL-CM5B, MIROC-ESM, MRI-CGCM3, MRI-ESM1, and NorESM1-ME.