Atmospheric Dynamics Feedback: Concept, Simulations, and Climate Implications
The regional climate response to radiative forcing is largely controlled by changes in the atmospheric circulation. It has been suggested that global climate sensitivity also depends on the circulation response, an effect called the "atmospheric dynamics feedback." Using a technique to isolate the influence of changes in atmospheric circulation on top-of-the-atmosphere radiation, the authors calculate the atmospheric dynamics feedback in coupled climate models. Large-scale circulation changes contribute substantially to all-sky and cloud feedbacks in the tropics but are relatively less important at higher latitudes. Globally averaged, the atmospheric dynamics feedback is positive and amplifies the near-surface temperature response to climate change by an average of 8% in simulations with coupled models. A constraint related to the atmospheric mass budget results in the dynamics feedback being small on large scales relative to feedbacks associated with thermodynamic processes. Idealized-forcing simulations suggest that circulation changes at high latitudes are potentially more effective at influencing global temperature than circulation changes at low latitudes, and the implications for past and future climate change are discussed.
© 2018 American Meteorological Society. (Manuscript received 13 July 2017, in final form 12 January 2018) We thank Paulo Ceppi, Reto Knutti, Paul O'Gorman, Brian Rose, Maria Rugenstein, and the editor for helpful comments, suggestions, and discussion. M.P.B. acknowledges support from the Imperial College London Research Fellowship Scheme.
Published - jcli-d-17-0470.1.pdf