On the Nature of the Arctic's Positive Lapse‐Rate Feedback
Robyn C. Boeke, Patrick C. Taylor, Sergio A. Sejas
Abstract
Abstract Radiative energy fluxes exiting the atmosphere toward the surface and to space are sensitive to the vertical structure of temperature. Under anthropogenic forcing, this sensitivity gives rise to the lapse‐rate feedback. Negative in the tropics and positive in the Arctic, studies argue that the lapse‐rate feedback is a primary cause of Arctic Amplification. While the negative tropical lapse‐rate feedback is understood mechanistically, the mechanics of the positive Arctic lapse‐rate feedback are less clear. Stable stratification is a necessary condition for the positive Arctic lapse‐rate feedback; however, does stable stratification place any further constraint on the feedback? We find that the magnitude, spatial variability, seasonality, and intermodel spread in the Arctic lapse‐rate feedback are dictated by the surface temperature change and not the degree of stable stratification. Our results support the multiprocess perspective of the Arctic lapse‐rate feedback, whereby the mechanisms responsible for the nonuniform warming profile determine the lapse‐rate feedback.