Critical Southern Ocean climate model biases traced to atmospheric model cloud errors
Hyder, P.; Edwards, J.M.; Allan, R.P.; Hewitt, H.T.; Bracegirdle, T.J.; Gregory, J.M.; Wood, R.A.; Meijers, A.J.S.; Mulcahy, J.; Field, P.; Furtado, K.; Bodas-Salcedo, A.; Williams, K.D.; Copsey, D.; Josey, S.A.; Liu, C.; Roberts, C.D.; Sanchez, C.; Ridley, J.; Thorpe, L.; Hardiman, S.C.; Mayer, M.; Berry, D.I.; Belcher, S.E. (2018). Critical Southern Ocean climate model biases traced to atmospheric model cloud errors. Nature Comm. 9(1): 17 pp. https://dx.doi.org/10.1038/s41467-018-05634-2
In: Nature Communications. Nature Publishing Group: London. ISSN 2041-1723; e-ISSN 2041-1723, more
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| Authors | | Top |
- Hyder, P.
- Edwards, J.M.
- Allan, R.P.
- Hewitt, H.T.
- Bracegirdle, T.J.
- Gregory, J.M.
- Wood, R.A.
- Meijers, A.J.S.
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- Mulcahy, J.
- Field, P.
- Furtado, K.
- Bodas-Salcedo, A.
- Williams, K.D.
- Copsey, D.
- Josey, S.A.
- Liu, C.
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- Roberts, C.D.
- Sanchez, C.
- Ridley, J.
- Thorpe, L.
- Hardiman, S.C.
- Mayer, M.
- Berry, D.I.
- Belcher, S.E.
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| Abstract |
The Southern Ocean is a pivotal component of the global climate system yet it is poorly represented in climate models, with significant biases in upper-ocean temperatures, clouds and winds. Combining Atmospheric and Coupled Model Inter-comparison Project (AMIP5/CMIP5) simulations, with observations and equilibrium heat budget theory, we show that across the CMIP5 ensemble variations in sea surface temperature biases in the 40–60°S Southern Ocean are primarily caused by AMIP5 atmospheric model net surface flux bias variations, linked to cloud-related short-wave errors. Equilibration of the biases involves local coupled sea surface temperature bias feedbacks onto the surface heat flux components. In combination with wind feedbacks, these biases adversely modify upper-ocean thermal structure. Most AMIP5 atmospheric models that exhibit small net heat flux biases appear to achieve this through compensating errors. We demonstrate that targeted developments to cloud-related parameterisations provide a route to better represent the Southern Ocean in climate models and projections. |
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