Separating the Influences of Low-Latitude Warming and Sea Ice Loss on Northern Hemisphere Climate Change

Journal Article · 14 April 2022 · Journal of Climate

DOI: https://doi.org/10.1175/JCLI-D-21-0180.1 · OSTI ID:1856608

Hay, Stephanie  ^[1]; Kushner, Paul J. ^[2]; Blackport, Russell ^[3]; McCusker, Kelly E. ^[4]; Oudar, Thomas ^[5]; Sun, Lantao ^[6]; England, Mark ^[7]; Deser, Clara ^[8]; Screen, James A. ^[1]; Polvani, Lorenzo M. ^[9]

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1. a University of Exeter, Exeter, United Kingdom
2. b University of Toronto, Toronto, Ontario, Canada
3. c Environment and Climate Change Canada, Victoria, British Columbia, Canada
4. d Rhodium Group, New York, New York
5. e CNRM, Université de Toulouse, Météo-France, CNRS, Toulouse, France
6. f Colorado State University, Fort Collins, Colorado
7. g University of Santa Cruz, Santa Cruz, California
8. h National Center for Atmospheric Research, Boulder, Colorado
9. i Columbia University, New York, New York

Abstract Analyzing a multimodel ensemble of coupled climate model simulations forced with Arctic sea ice loss using a two-parameter pattern-scaling technique to remove the cross-coupling between low- and high-latitude responses, the sensitivity to high-latitude sea ice loss is isolated and contrasted to the sensitivity to low-latitude warming. Despite some differences in experimental design, the Northern Hemisphere near-surface atmospheric sensitivity to sea ice loss is found to be robust across models in the cold season; however, a larger intermodel spread is found at the surface in boreal summer, and in the free tropospheric circulation. In contrast, the sensitivity to low-latitude warming is most robust in the free troposphere and in the warm season, with more intermodel spread in the surface ocean and surface heat flux over the Northern Hemisphere. The robust signals associated with sea ice loss include upward turbulent and longwave heat fluxes where sea ice is lost, warming and freshening of the Arctic Ocean, warming of the eastern North Pacific Ocean relative to the western North Pacific with upward turbulent heat fluxes in the Kuroshio Extension, and salinification of the shallow shelf seas of the Arctic Ocean alongside freshening in the subpolar North Atlantic Ocean. In contrast, the robust signals associated with low-latitude warming include intensified ocean warming and upward latent heat fluxes near the western boundary currents, freshening of the Pacific Ocean, salinification of the North Atlantic, and downward sensible and longwave fluxes over the ocean.

• Research Organization: Univ. of California, Irvine, CA (United States)
• Sponsoring Organization: USDOE; USDOE Office of Science (SC)
• Grant/Contract Number: SC0019407
• OSTI ID: 1856608
• Journal Information: Journal of Climate, Journal Name: Journal of Climate Journal Issue: 8 Vol. 35; ISSN 0894-8755
• Publisher: American Meteorological SocietyCopyright Statement
• Country of Publication: United States
• Language: English