Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic
<p>Atmospheric blocking can influence Arctic weather by diverting the mean westerly flow and steering cyclones polewards, bringing warm, moist air to high latitudes. Recent studies have shown that diabatic heating processes in the ascending warm conveyor belt branch of extratropical cyclones a...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Copernicus Publications
2022-01-01
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| Series: | Weather and Climate Dynamics |
| Online Access: | https://wcd.copernicus.org/articles/3/21/2022/wcd-3-21-2022.pdf |
| _version_ | 1798035359202803712 |
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| author | S. Murto R. Caballero G. Svensson L. Papritz |
| author_facet | S. Murto R. Caballero G. Svensson L. Papritz |
| author_sort | S. Murto |
| collection | DOAJ |
| description | <p>Atmospheric blocking can influence Arctic weather by diverting the mean
westerly flow and steering cyclones polewards, bringing warm, moist air to
high latitudes. Recent studies have shown that diabatic heating processes in
the ascending warm conveyor belt branch of extratropical cyclones are relevant
to blocking dynamics. This leads to the question of the extent to which
diabatic heating associated with mid-latitude cyclones may influence
high-latitude blocking and drive Arctic warm events. In this study we
investigate the dynamics behind 50 extreme warm events of wintertime high-Arctic temperature anomalies during 1979–2016. Classifying the warm events
based on blocking occurrence within three selected sectors, we find that 30 of
these events are associated with a block over the Urals, featuring negative
upper-level potential vorticity (PV) anomalies over central Siberia north of
the Ural Mountains. Lagrangian back-trajectory calculations show that almost
60 <span class="inline-formula">%</span> of the air parcels making up these negative PV anomalies experience
lifting and diabatic heating (median 11 <span class="inline-formula">K</span>) in the 6 d prior to the
block. Further, almost 70 <span class="inline-formula">%</span> of the heated trajectories undergo maximum
heating in a compact region of the mid-latitude North Atlantic, temporally
taking place between 6 and 1 d before arriving in the blocking
region. We also find anomalously high cyclone activity (on average five
cyclones within this 5 d heating window) within a sector northwest of the
main heating domain. In addition, 10 of the 50 warm events are associated with
blocking over Scandinavia. Around 60 <span class="inline-formula">%</span> of the 6 d back trajectories
started from these blocks experience diabatic heating, of which 60 <span class="inline-formula">%</span> undergo
maximum heating over the North Atlantic but generally closer to the time of
arrival in the block and further upstream relative to heated trajectories
associated with Ural blocking. This study suggests that, in addition to the
ability of blocks to guide cyclones northwards, Atlantic cyclones play a
significant role in the dynamics of high-latitude blocking by providing low-PV
air via moist-diabatic processes. This emphasizes the importance of the mutual
interactions between mid-latitude cyclones and Eurasian blocking for
wintertime Arctic warm extremes.</p> |
| first_indexed | 2024-04-11T20:57:06Z |
| format | Article |
| id | doaj.art-112cbfffe0224ac2ba3ae039057a7416 |
| institution | Directory Open Access Journal |
| issn | 2698-4016 |
| language | English |
| last_indexed | 2024-04-11T20:57:06Z |
| publishDate | 2022-01-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Weather and Climate Dynamics |
| spelling | doaj.art-112cbfffe0224ac2ba3ae039057a74162022-12-22T04:03:38ZengCopernicus PublicationsWeather and Climate Dynamics2698-40162022-01-013214410.5194/wcd-3-21-2022Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high ArcticS. Murto0R. Caballero1G. Svensson2L. Papritz3Department of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, SwedenDepartment of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, SwedenDepartment of Meteorology and Bolin Centre for Climate Research, Stockholm University, Stockholm, SwedenInstitute for Atmospheric and Climate Science, ETH Zürich, Zurich, Switzerland<p>Atmospheric blocking can influence Arctic weather by diverting the mean westerly flow and steering cyclones polewards, bringing warm, moist air to high latitudes. Recent studies have shown that diabatic heating processes in the ascending warm conveyor belt branch of extratropical cyclones are relevant to blocking dynamics. This leads to the question of the extent to which diabatic heating associated with mid-latitude cyclones may influence high-latitude blocking and drive Arctic warm events. In this study we investigate the dynamics behind 50 extreme warm events of wintertime high-Arctic temperature anomalies during 1979–2016. Classifying the warm events based on blocking occurrence within three selected sectors, we find that 30 of these events are associated with a block over the Urals, featuring negative upper-level potential vorticity (PV) anomalies over central Siberia north of the Ural Mountains. Lagrangian back-trajectory calculations show that almost 60 <span class="inline-formula">%</span> of the air parcels making up these negative PV anomalies experience lifting and diabatic heating (median 11 <span class="inline-formula">K</span>) in the 6 d prior to the block. Further, almost 70 <span class="inline-formula">%</span> of the heated trajectories undergo maximum heating in a compact region of the mid-latitude North Atlantic, temporally taking place between 6 and 1 d before arriving in the blocking region. We also find anomalously high cyclone activity (on average five cyclones within this 5 d heating window) within a sector northwest of the main heating domain. In addition, 10 of the 50 warm events are associated with blocking over Scandinavia. Around 60 <span class="inline-formula">%</span> of the 6 d back trajectories started from these blocks experience diabatic heating, of which 60 <span class="inline-formula">%</span> undergo maximum heating over the North Atlantic but generally closer to the time of arrival in the block and further upstream relative to heated trajectories associated with Ural blocking. This study suggests that, in addition to the ability of blocks to guide cyclones northwards, Atlantic cyclones play a significant role in the dynamics of high-latitude blocking by providing low-PV air via moist-diabatic processes. This emphasizes the importance of the mutual interactions between mid-latitude cyclones and Eurasian blocking for wintertime Arctic warm extremes.</p>https://wcd.copernicus.org/articles/3/21/2022/wcd-3-21-2022.pdf |
| spellingShingle | S. Murto R. Caballero G. Svensson L. Papritz Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic Weather and Climate Dynamics |
| title | Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic |
| title_full | Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic |
| title_fullStr | Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic |
| title_full_unstemmed | Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic |
| title_short | Interaction between Atlantic cyclones and Eurasian atmospheric blocking drives wintertime warm extremes in the high Arctic |
| title_sort | interaction between atlantic cyclones and eurasian atmospheric blocking drives wintertime warm extremes in the high arctic |
| url | https://wcd.copernicus.org/articles/3/21/2022/wcd-3-21-2022.pdf |
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