EVALUATING CLIMATE MODELS WITH AN AFRICAN LENS

• Published in: Bulletin of the American Meteorological Society 2018-02, Vol.99 (2), p.313-336
• Main Authors: James, Rachel, Washington, Richard, Abiodun, Babatunde, Kay, Gillian, Mutemi, Joseph, Pokam, Wilfried, Hart, Neil, Artan, Guleid, Senior, Cath
• Format: Article
• Language: English
• Subjects: Analysis; Book publishing; Climate adaptation; Climate change; Climate change adaptation; Climate models; Computer simulation; Dynamics; Evaluation; General circulation models; Laboratories; Precipitation; Rain; Regional climates; Regions; Scientists
• ISSN: 0003-0007; 1520-0477
• DOI: 10.1175/BAMS-D-16-0090.1

Climate models are becoming evermore complex and increasingly relied upon to inform climate change adaptation. Yet progress in model development is lagging behind in many of the regions that need the information most, including in Africa. Targeted model development for Africa is crucial and so too is targeted model evaluation. Assessment of model performance in specific regions often follows a “validation” approach, focusing on mean biases, but if models are to be improved, it is important to understand how they simulate regional climate dynamics: to move from validation to process-based evaluation. This evaluation may be different for every region and requires local weather and climate expertise: a “one size fits all” approach could overlook important, region-specific phenomena. So which are the important processes in African regions? And how might they be evaluated? This paper addresses these questions, drawing on the expertise of a team of scientists from central, East, southern, and West Africa. For each region, the current understanding of climate models is reviewed, and an example of targeted evaluation is provided, including analysis of moist circulations, teleconnections, and modes of variability. A pan-African perspective is also considered, to examine processes operating between regions. The analysis is based on the Met Office Unified Model, but it uses diagnostics that might be applied to other models. These examples are intended to prompt further discussion among climate modelers and African scientists about how to best evaluate models with an African lens, and promote the development of a model evaluation hub for Africa, to fast track our understanding of model behavior for this important continent.