A global climate model performance atlas for the southern hemisphere extratropics based on regional atmospheric circulation patterns

Abstract

The performance of 61 global climate models participating in CMIP5 and 6 is evaluated for the Southern Hemisphere extratropics in terms of typical regional-scale atmospheric circulation patterns. These patterns are known to be linked with a number of key variables in atmospheric physics and chemistry and provide an overarching concept for model evaluation. First, hemispheric-wide error and ranking maps are provided for each model and regional details are described. Then, the results are compared with those obtained in a companion study for the Northern Hemisphere. For most models, the average error magnitude and ranking position is similar on both hemispheres, ruling out systematic tuning toward either of the two. CMIP6 models perform better on average than CMIP5 models and the interactive simulation of more climate system components does not deteriorate the results for most model families. Better performance is associated with higher resolution in the atmosphere, following a non-linear relationship.

[Plain Language Summary] This letter provides a survey on the capability of global climate models to reproduce the regional atmospheric circulation in the Southern Hemisphere in present climate conditions. Climate models from the latest model generation are found to perform better on average than those of the previous generation and the obtained model ranking is similar to that found for the Northern Hemisphere in a companion study. While model performance is found to be generally unrelated to model complexity in terms of covered climate system components, better results are associated with higher model resolution in the atmosphere.