Paying Attention to Details Can Improve Global Climate Models
Global models typically cannot simulate the small-scale wind gustiness that results from ocean-eddy sized variations in water temperature yet this gustiness affects processes in the atmospheric surface air as well as the overlying clouds. A recently published, DOE supported analysis of Community Climate System Model (CCSM) experiments used high-resolution satellite observations, such as surface winds and sea surface temperature, to challenge the fidelity of high-resolution climate simulations. The study found that these fine-scale features are captured only when the ocean model resolution is so great that it is able to resolve ocean eddies. However, the features are still weaker than observed, even if the atmospheric resolution is increased. This suggests that better sub-grid scale parameterizations of the atmospheric processes are needed, and not just increased atmospheric model resolution. This research provides insight into the best modeling approaches for simulating the climate impacts of small-scale features at the ocean-air interface. We anticipate that improved parameterizations based on this approach will potentially remove biases and reduce uncertainties in climate predictions.
Bryan, F.O., R. Tomas, J. M. Dennis, D. B. Chelton, N.G. Loeb, and J. L. McClean. 2010. “Frontal Scale Air-Sea Interaction in High-Resolution Coupled Climate Models,” Journal of Climate 23:6277-91.