Increased Ocean Heat Convergence Into the High Latitudes With CO2 Doubling Enhances Polar‐Amplified Warming. Issue 20 (18th October 2017)

• Record Type: Journal Article
• Authors: Singh, H. A.; Rasch, P. J.; Rose, B. E. J.
• Is Part Of: Geophysical research letters. Volume 44:Issue 20(2017)
• Page Start: 10, 583
• Page End: 10, 591
• Publication Date: 2017-10-18
• Subjects: polar climate change -- lapse rate feedback -- ocean dynamics -- Bjerknes feedback -- polar amplification -- winter sea ice retreat; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2017GL074561
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: We isolate the role of the ocean in polar climate change by directly evaluating how changes in ocean dynamics with quasi‐equilibrium CO2 doubling impact high‐latitude climate. With CO2 doubling, the ocean heat flux convergence (OHFC) shifts poleward in winter in both hemispheres. Imposing this pattern of perturbed OHFC in a global climate model results in a poleward shift in ocean‐to‐atmosphere turbulent heat fluxes (both sensible and latent) and sea ice retreat; the high latitudes warm, while the midlatitudes cool, thereby amplifying polar warming. Furthermore, midlatitude cooling is propagated to the polar midtroposphere on isentropic surfaces, augmenting the (positive) lapse rate feedback at high latitudes. These results highlight the key role played by the partitioning of meridional energy transport changes between the atmosphere and ocean in high‐latitude climate change. Key Points: With CO2 doubling, the ocean heat flux convergence shifts poleward in winter in both hemispheres These changes in the ocean heat flux convergence amplify polar warming and damp extrapolar warming Decreased extrapolar warming contributes to the enhanced high‐latitude lapse rate feedback