Different mechanisms of Arctic and Antarctic sea ice response to ocean heat transport

Aylmer, J. ORCID: https://orcid.org/0000-0002-5159-0608, Ferreira, D. ORCID: https://orcid.org/0000-0003-3243-9774 and Feltham, D. ORCID: https://orcid.org/0000-0003-2289-014X (2022) Different mechanisms of Arctic and Antarctic sea ice response to ocean heat transport. Climate Dynamics, 59. pp. 315-329. ISSN 1432-0894 doi: 10.1007/s00382-021-06131-x

Abstract/Summary

Understanding drivers of Arctic and Antarctic sea ice on multidecadal timescales is key to reducing uncertainties in long-term climate projections. Here we investigate the impact of Ocean Heat Transport (OHT) on sea ice, using pre-industrial control simulations of 20 models participating in the latest Coupled Model Intercomparison Project (CMIP6). In all models and in both hemispheres, sea ice extent is negatively correlated with poleward OHT. However, the similarity of the correlations in both hemispheres hides radically different underlying mechanisms. In the northern hemisphere, positive OHT anomalies primarily result in increased ocean heat convergence along the Atlantic sea ice edge, where most of the ice loss occurs. Such strong, localised heat fluxes (~100 W/m^2) also drive increased atmospheric moist-static energy convergence at higher latitudes, resulting in a pan-Arctic reduction in sea ice thickness. In the southern hemisphere, increased OHT is released relatively uniformly under the Antarctic ice pack, so that associated sea ice loss is driven by basal melt with no direct atmospheric role. These results are qualitatively robust across models and strengthen the case for a substantial contribution of ocean forcing to sea ice uncertainty, and biases relative to observations, in climate models.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/102179
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	Springer
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