Impacts of oceanic and atmospheric heat transports on sea-ice extent

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 (2020) Impacts of oceanic and atmospheric heat transports on sea-ice extent. Journal of Climate, 33 (16). pp. 7197-7215. ISSN 1520-0442 doi: 10.1175/JCLI-D-19-0761.1

Abstract/Summary

Climate-model biases in Ocean Heat Transport (OHT) have been proposed as a major contributor to uncertainties in projections of sea-ice extent. To better understand the impact of OHT on sea-ice extent and compare it to that of Atmospheric Heat Transport (AHT), an idealised, zonally-averaged Energy-Balance Model (EBM) is developed. This is distinguished from previous EBM work by coupling a diffusive mixed-layer OHT and a prescribed OHT contribution, with an atmospheric EBM and a reduced-complexity sea-ice model. The ice-edge latitude is roughly linearly related to the convergence of each heat transport component, with different sensitivities depending on whether the ice cover is perennial or seasonal. In both regimes, Bjerknes Compensation (BC) occurs such that the response of AHT partially offsets the impact of changing OHT. As a result, the effective sensitivity of ice-edge retreat to increasing OHT is only ∼2/3 of the actual sensitivity (i.e. eliminating the BC effect). In the perennial regime, the sensitivity of the ice edge to OHT is about twice that to AHT, while in the seasonal regime they are similar. The ratio of sensitivities is, to leading order, determined by atmospheric longwave feedback parameters in the perennial regime. Here, there is no parameter range in which the ice edge is more sensitive to AHT than OHT.

Item Type	Article
URI	https://reading-clone.eprints-hosting.org/id/eprint/91173
Item Type	Article
Refereed	Yes
Divisions	Science > School of Mathematical, Physical and Computational Sciences > Department of Meteorology
Publisher	American Meteorological Society
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