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Serious Climate Model Biases in Earth's Eastern Tropical Oceans

Paper Reviewed
Richter, I. 2015. Climate model biases in the eastern tropical oceans: causes, impacts and ways forward. WIREs Climate Change 6: 345-358.

Writing as background for his work, Ingo Richter states that "the eastern boundaries of the tropical and subtropical oceans ... feature extensive stratocumulus cloud decks that play a pivotal role in the response of the climate system to greenhouse gas forcing." And, unfortunately, he notes that "global climate models experience great difficulties simulating eastern boundary regions, with one of the most notable shortcomings being warm sea-surface temperature biases that often exceed 5 K."

More specifically, the Japanese scientist's extensive review of the subject led him to conclude that (1) "weaker than observed alongshore winds lead to an under-representation of [i] upwelling and [ii] alongshore currents and [iii] the cooling associated with them," that (2) "stratocumulus decks and their effects on shortwave radiation are under-predicted in the models," that (3) "the offshore transport of cool waters by mesoscale eddies is not adequately represented by global models due to insufficient resolution," and that (4) "the sharp vertical temperature gradient separating the warm upper ocean layer from the deep ocean is too diffuse in the models."

And where does all this leave us? Richter concludes that "while there is certainly hope that biases will gradually be reduced, it appears that we will have to continue to deal with them for the next decade or longer."

Posted 21 December 2015