Preprints
https://doi.org/10.5194/egusphere-2024-2506
https://doi.org/10.5194/egusphere-2024-2506
16 Aug 2024
 | 16 Aug 2024

Minimal influence of future Arctic sea ice loss on North Atlantic jet stream morphology

Yvonne Anderson, Jacob Perez, and Amanda C. Maycock

Abstract. The response of the North Atlantic jet stream to Arctic sea ice loss has been a topic of substantial scientific debate. Some studies link declining Arctic sea ice to a weaker, wavier jet stream, which potentially increases the occurrence of extreme weather events. Other studies suggest no causal link between Arctic sea ice loss and the jet stream, instead attributing jet variations to internal variability. Current methods for characterising the low-level jet typically use zonal wind speeds averaged over the North Atlantic sector, which can result in the loss of important aspects of jet morphology. This study uses a new 2-dimensional feature-based method to investigate the winter low-level jet response to future Arctic sea ice loss using idealised prescribed sea ice experiments from the Polar Amplification Model Intercomparison Project (PAMIP). In contrast to earlier studies that have focused on seasonal average changes, this study also explores how daily jet variability is altered by sea ice loss. The results show a significant equatorward shift in mean jet latitude for three of the six PAMIP models analysed, with a multi-model mean jet shift of -0.8 ± 0.1°. However, there is no change in jet speed and jet tilt across all models and no robust change in jet mass (area-weighted speed). Three of the six models show an increase in the frequency of split jet days, but this does not strongly affect the overall distributions of daily jet latitude, speed and mass. Likewise, the results show no significant change in the daily variability of jet features and changes in interannual variability are inconsistent between the models. The results extend previous studies characterising jet response from a zonally averaged perspective, and suggest it is unlikely that future Arctic sea ice loss will cause significant weakening of the North Atlantic jet stream or an increase in jet variability.

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Yvonne Anderson, Jacob Perez, and Amanda C. Maycock

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-2506', Kristian Strommen, 28 Aug 2024
    • AC1: 'Reply on RC1', Yvonne Anderson, 03 Nov 2024
  • RC2: 'Comment on egusphere-2024-2506', Raphael Köhler, 04 Sep 2024
    • AC2: 'Reply on RC2', Yvonne Anderson, 03 Nov 2024
  • RC3: 'Comment on egusphere-2024-2506', Russell Blackport, 14 Sep 2024
    • AC3: 'Reply on RC3', Yvonne Anderson, 03 Nov 2024
Yvonne Anderson, Jacob Perez, and Amanda C. Maycock

Data sets

Jet feature data from PAMIP model simulations Yvonne Anderson https://doi.org/10.5281/zenodo.8279707

Coupled Model Intercomparison Project (Phase 6) datasets WCRP https://esgf-ui.ceda.ac.uk/cog/projects/cmip6-ceda/

ERA-5 reanalysis data H. Hersbach et al. https://doi.org/10.24381/cds.143582cf

Model code and software

Eddy-Driven Jet Object (EDJO) identification methodology Jacob Perez https://github.com/scjpleeds/EDJO-identification

Yvonne Anderson, Jacob Perez, and Amanda C. Maycock

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Short summary
The impact of Arctic sea ice loss on the North Atlantic jet stream is debated, with some linking changes to ice loss and others to natural variability. This study uses a new method to explore how future sea ice loss will affect the jet stream. In half of the models, the jet shifts equatorward, but its speed and tilt are unchanged. Some models also exhibit more jet splitting. The results suggest that future sea ice loss is unlikely to significantly weaken the jet stream or make it more variable.