Climate Models Lack Jet–Rainfall Coupling over West Africa
Changes in large-scale dynamics over West Africa-the strength and position of zonal jets-are a key interim step by which local and remote forcing is communicated into changes in rainfall. This study identifies a key mode of jet variability and demonstrates how it is strongly coupled with rainfall. T...
| Main Authors: | , , , |
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| Format: | Article |
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American Meteorological Society
2018
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| Online Access: | http://hdl.handle.net/1721.1/114588 https://orcid.org/0000-0002-5364-8543 https://orcid.org/0000-0002-8362-4761 |
| Summary: | Changes in large-scale dynamics over West Africa-the strength and position of zonal jets-are a key interim step by which local and remote forcing is communicated into changes in rainfall. This study identifies a key mode of jet variability and demonstrates how it is strongly coupled with rainfall. The approach provides a quantitative framework to assess jet-rainfall coupling and a useful tool to investigate the concerning spread in CMIP5 rainfall projections over the West African Sahel. It is shown that many CMIP5 simulations fail to capture this coupling, indicating a fundamental limitation in their ability to predict future rainfall conditions. The results demonstrate that West African rainfall in the coming CMIP6 ensemble should be interpreted with caution; key atmospheric processes that deliver rainfall must be validated before conducting detailed analysis on rainfall. Keywords: Africa; Dynamics; Jets; Monsoons; Hydrometeorology; Model evaluation/performance |
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