North Atlantic polar lows and weather regimes: do current links persist in a warmer climate?

Mallet, Paul-Etienne; Claud, Chantal; Vicomte, Marie

doi:10.1002/asl.763

Cited by 10 publications

(20 citation statements)

References 28 publications

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“…Long‐term future changes of CAO occurrence in the Nordic Seas in a warming climate, in contrast, may not primarily be caused by changes of the large‐scale circulation. In fact, climate integrations indicate that the frequency of Euro‐Atlantic WRs in a considerably warmer climate will undergo modest changes only (Mallet et al, ). Hence, long‐term changes in the occurrence of CAOs over the Nordic Seas in a warming climate will most likely be dominated by changes in the availability of cold (with respect to SST) air masses and shifts in CAO formation regions associated with the retreating ice edge (e.g., Fauria et al, ).…”

Section: Discussionmentioning

confidence: 99%

Linking Low‐Frequency Large‐Scale Circulation Patterns to Cold Air Outbreak Formation in the Northeastern North Atlantic

Papritz

Grams

2018

Geophysical Research Letters

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The regional variability of wintertime marine cold air outbreaks (CAOs) in the northeastern North Atlantic is studied focusing on the role of weather regimes in modulating the large‐scale circulation. Each regime is characterized by a typical CAO frequency anomaly pattern and a corresponding imprint in air‐sea heat fluxes. Cyclonically dominated regimes, Greenland blocking and the Atlantic ridge regime are found to provide favorable conditions for CAO formation in at least one major sea of the study region; CAO occurrence is suppressed, however, by blocked regimes whose associated anticyclones are centered over northern Europe (European / Scandinavian blocking). Kinematic trajectories reveal that strength and location of the storm tracks are closely linked to the pathways of CAO air masses and, thus, CAO occurrence. Finally, CAO frequencies are also linked to the strength of the stratospheric polar vortex, which is understood in terms of associated variations in the frequency of weather regimes.

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Section: Discussionmentioning

confidence: 99%

Linking Low‐Frequency Large‐Scale Circulation Patterns to Cold Air Outbreak Formation in the Northeastern North Atlantic

Papritz

Grams

2018

Geophysical Research Letters

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“…In the Barents Sea however, there are no significant changes. Mallet et al (2017) found that circulation patterns give a reduced influence on the static stability in the future, as sea-ice retreat reduces the variability. The historical link between circulation pattern and static stability (and thus as a proxy for polar lows) is therefore not the same in the future, posing a challenge when using it as part of a statistical downscaling approach.…”

Section: Mcao In Relation To Circulation Patternsmentioning

confidence: 98%

Projected future changes in Marine Cold-Air Outbreaks associated with Polar Lows in the Northern North-Atlantic Ocean

2019

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Marine Cold-Air Outbreaks (MCAO) can be used as a large-scale measure of the potential for development of Polar Lows in the Northern North Atlantic Ocean during NH winter. We applied an MCAO index to 30 members of the Community Earth System Model Large Ensemble to investigate model-projected future changes in the Nordic and Barents Seas in response to anthropogenic climate change. In agreement with previous studies we found an overall decrease in the MCAO index due to increased tropospheric static stability. We also found a changed seasonal profile, with a stronger decrease in December-January than in February-March, effectively leading to the peak occurring in February rather than January in the Nordic Seas. In the Barents Sea, the reductions were only statistically significant in the autumn and spring, with the winter reduction due to increased static stability was partly balanced by a retracting sea-ice edge. The contribution from circulation changes in mean sea-level pressure was assessed by a cluster analysis in lower-dimensional phase-space, spanned by the projections onto the four leading Empirical Orthogonal Functions. While there was a small but statistically significant increase of the Atlantic Ridge-like pattern, the overall changes in MCAO were dominated by changes in temperature at the sea surface and aloft.

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“…Global warming will lead to an increase in the static stability of the atmosphere in the North Atlantic (Zahn and von Storch, 2010;Mallet et al, 2017;Landgren et al, 2019b) and in the North Pacific, although the increase will be smaller in the latter (Landgren et al, 2019b). In the North Atlantic, the SST -T 500 will decrease almost everywhere where PLs develop, and situations of high vertical instability will become less frequent (Mallet et al, 2017). Moreover, the loss of sea ice will lead to a change on the spatial distribution of atmospheric static stability.…”

Section: Impact Of Climate Change On the Climatology Of Plsmentioning

confidence: 99%

Recent advances in polar low research: current knowledge, challenges and future perspectives

Moreno-Ibáñez

Laprise

Gachon

2021

Tellus A: Dynamic Meteorology and Oceanography

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Polar lows (PLs) are high-latitude intense maritime mesoscale weather systems that develop over open water near the sea ice margin or near snow-covered continents during cold air outbreaks. PLs pose a threat to coastal and island communities, transportation and offshore drilling platforms. PLs mainly develop during the cold season and their frequency exhibits a large interannual variability. Observations from polar-orbiting satellites are the main source of observational data to study PLs since conventional observations are sparse and unevenly distributed in high latitudes. PL forecasting has long remained a challenge due to the small size and short lifetime of these systems. Nevertheless, the representation of PLs in numerical models has significantly improved with the advent of high-resolution atmospheric models. Several studies have shown that baroclinic instability and convection play an important role in the development of PLs, but a thorough understanding of the physical mechanisms involved in the formation and intensification of PLs is yet to be developed. The relevant role of surface sensible heat flux and latent heat release in PL development has often been highlighted. The diabatic fluxes from the oceanic surface and associated with PLs can cause a decrease in the sea surface temperature (SST), whereas the strong wind speeds can lead to upper-ocean mixing in regions where an ocean temperature inversion is present. It is expected that global warming associated with anthropogenic climate changes may lead to an increase in the static stability of the atmosphere, thus affecting the climatology of PLs. In the North Atlantic the regions of PL activity will shift northwards as seasonal seaice margins migrate towards higher latitudes areas, and the frequency of PLs will decrease. Although our knowledge about PLs has significantly increased during the last decades, the are still many unanswered questions. Among the most pressing issues in PL research are the need to determine the objective criteria that define PLs and to devise an international intercomparison project of PL detection and tracking.

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North Atlantic polar lows and weather regimes: do current links persist in a warmer climate?

Cited by 10 publications

References 28 publications

Linking Low‐Frequency Large‐Scale Circulation Patterns to Cold Air Outbreak Formation in the Northeastern North Atlantic

Linking Low‐Frequency Large‐Scale Circulation Patterns to Cold Air Outbreak Formation in the Northeastern North Atlantic

Projected future changes in Marine Cold-Air Outbreaks associated with Polar Lows in the Northern North-Atlantic Ocean

Recent advances in polar low research: current knowledge, challenges and future perspectives

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