Sea ice and atmospheric circulation shape the high-latitude lapse rate feedback

• Published in: NPJ climate and atmospheric science Vol. 3; no. 1
• Main Authors: Feldl, Nicole, Po-Chedley, Stephen, Singh, Hansi K. A., Hay, Stephanie, Kushner, Paul J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22.10.2020; Nature Publishing Group; Springer Nature
• Subjects: 704/106/125; 704/106/35/823; 704/106/694; Albedo; Amplification; Anthropogenic factors; Atmospheric circulation; atmospheric dynamic; Atmospheric Protection/Air Quality Control/Air Pollution; Atmospheric Sciences; Climate change; Climate Change/Climate Change Impacts; Climatology; cryospheric science; Earth and Environmental Science; Earth Sciences; ENVIRONMENTAL SCIENCES; Feedback; Human influences; Lapse rate; Latitude; Long wave radiation; Oceans; Sea ice; Solar radiation; Troposphere; Arctic region
• ISSN: 2397-3722; 2397-3722
• DOI: 10.1038/s41612-020-00146-7

Arctic amplification of anthropogenic climate change is widely attributed to the sea-ice albedo feedback, with its attendant increase in absorbed solar radiation, and to the effect of the vertical structure of atmospheric warming on Earth’s outgoing longwave radiation. The latter lapse rate feedback is subject, at high latitudes, to a myriad of local and remote influences whose relative contributions remain unquantified. The distinct controls on the high-latitude lapse rate feedback are here partitioned into “upper” and “lower” contributions originating above and below a characteristic climatological isentropic surface that separates the high-latitude lower troposphere from the rest of the atmosphere. This decomposition clarifies how the positive high-latitude lapse rate feedback over polar oceans arises primarily as an atmospheric response to local sea ice loss and is reduced in subpolar latitudes by an increase in poleward atmospheric energy transport. The separation of the locally driven component of the high-latitude lapse rate feedback further reveals how it and the sea-ice albedo feedback together dominate Arctic amplification as a coupled mechanism operating across the seasonal cycle.