Patterns of sea ice retreat in the transition to a seasonally ice-free arctic

Patricia DeRepentigny, L. Bruno Tremblay, Robert Newton, Stephanie Pfirman

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

The patterns of sea ice retreat in the Arctic Ocean are investigated using two global climate models (GCMs) that have profound differences in their large-scale mean winter atmospheric circulation and sea ice drift patterns. The Community Earth System Model Large Ensemble (CESM-LE) presents a mean sea level pressure pattern that is in general agreement with observations for the late twentieth century. The Community Climate System Model, version 4 (CCSM4), exhibits a low bias in its mean sea level pressure over the Arctic region with a deeper Icelandic low. A dynamical mechanism is presented in which large-scale mean winter atmospheric circulation has significant effect on the following September sea ice extent anomaly by influencing ice divergence in specific areas. A Lagrangian model is used to backtrack the 80°N line from the approximate time of the melt onset to its prior positions throughout the previous winter and quantify the divergence across the Pacific and Eurasian sectors of the Arctic. It is found that CCSM4 simulates more sea ice divergence in the Beaufort and Chukchi Seas and less divergence in the Eurasian seas when compared to CESM-LE, leading to a Pacific-centric sea ice retreat. On the other hand, CESM-LE shows a more symmetrical retreat between the Pacific, Eurasian, and Atlantic sectors of the Arctic. Given that a positive trend in the Arctic Oscillation (AO) index, associated with low sea level pressure anomalies in the Arctic, is a robust feature of GCMs participating in phase 5 of the Coupled Model Intercomparison Project (CMIP5), these results suggest that the sea ice retreat in the Pacific sector could be amplified during the transition to a seasonal ice cover.

Original languageEnglish (US)
Pages (from-to)6993-7008
Number of pages16
JournalJournal of Climate
Volume29
Issue number19
DOIs
StatePublished - Jan 1 2016
Externally publishedYes

Keywords

  • Arctic oscillation
  • Circulation/dynamics
  • Climate models
  • Climate prediction
  • General circulation models
  • Models and modeling
  • Physical meteorology and climatology

ASJC Scopus subject areas

  • Atmospheric Science

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