Journal cover Journal topic
Weather and Climate Dynamics An interactive open-access journal of the European Geosciences Union
Journal topic

Abstracted/indexed

Abstracted/indexed
Discussion papers
https://doi.org/10.5194/wcd-2019-11
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/wcd-2019-11
© Author(s) 2019. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 14 Nov 2019

Submitted as: research article | 14 Nov 2019

Review status
This discussion paper is a preprint. It is a manuscript under review for the journal Weather and Climate Dynamics (WCD).

Intermittency of Arctic-midlatitude teleconnections: stratospheric pathway between autumn sea ice and the winter NAO

Peter Yu Feng Siew1,2, Camille Li1,2, Stefan Pieter Sobolowski3,2, and Martin Peter King3,2 Peter Yu Feng Siew et al.
  • 1Geophysical Institute, University of Bergen, Bergen, Norway
  • 2Bjerknes Centre for Climate Research, Bergen, Norway
  • 3NORCE, Bergen, Norway

Abstract. There is an observed relationship linking Arctic sea ice conditions in autumn to midlatitude weather the following winter. Of interest in this study is a hypothesized stratospheric pathway whereby reduced sea ice in the Barents-Kara Seas enhances upward wave activity and wave-breaking in the stratosphere, leading to a weakening of the polar vortex and a transition of the North Atlantic Oscillation (NAO) to its negative phase. A Causal Effect Networks (CEN) framework is used to explore the stratospheric pathway between late autumn Barents-Kara sea ice and the February NAO, focusing on its seasonal evolution, timescale-dependence, and robustness. Results indicate that the pathway is statistically detectable and has been relatively “active” over the 39-year observational period used here, explaining approximately 26 % of the interannual variability in the February NAO. However, a bootstrap-based resampling test reveals that the pathway is highly intermittent: the full stratospheric pathway appears in only 15 % of the sample populations derived from observations, with individual causal linkages ranging from 44 to 85 % in occurrence rates. The pathway’s intermittency is consistent with the weak signal-to-noise ratio of the atmospheric response to Arctic sea ice variability in modelling experiments, and suggests that Arctic-midlatitude teleconnections might be favoured in certain background states. On shorter time scales, the CEN detects two-way interactions between Barents-Kara sea ice and the midlatitude circulation that indicate a role for synoptic variability associated with blocking over the Urals region and moist air intrusions from the Euro-Atlantic sector. This synoptic variability has the potential to interfere with the stratospheric pathway, thereby contributing to its intermittency. This study helps quantify the robustness of causal linkages within the stratospheric pathway, and provides insight into which linkages are most subject to sampling issues within the relatively short observational record. Overall, the results should help guide the analysis and design of ensemble modelling experiments required to improve physical understanding of Arctic-midlatitude teleconnections.

Peter Yu Feng Siew et al.
Interactive discussion
Status: open (until 26 Dec 2019)
Status: open (until 26 Dec 2019)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement
Peter Yu Feng Siew et al.
Peter Yu Feng Siew et al.
Viewed  
Total article views: 148 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
104 38 6 148 21 1 1
  • HTML: 104
  • PDF: 38
  • XML: 6
  • Total: 148
  • Supplement: 21
  • BibTeX: 1
  • EndNote: 1
Views and downloads (calculated since 14 Nov 2019)
Cumulative views and downloads (calculated since 14 Nov 2019)
Viewed (geographical distribution)  
Total article views: 124 (including HTML, PDF, and XML) Thereof 124 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Cited  
Saved  
No saved metrics found.
Discussed  
No discussed metrics found.
Latest update: 09 Dec 2019
Publications Copernicus
Download
Short summary
Arctic sea ice loss has been linked to changes in midlatitude weather and climate. However, the literature offers differing views on the strength, robustness, and even existence of these linkages. We use a statistical tool (Causal Effect Networks) to show that one proposed pathway linking Barents-Kara ice and the midlatitude circulation is intermittent in observations, and likely only active under certain conditions. This result may help explain apparent inconsistencies across previous studies.
Arctic sea ice loss has been linked to changes in midlatitude weather and climate. However, the...
Citation