Life cycle dynamics of Greenland blocking from a potential vorticity perspective
Blocking over Greenland stands out in comparison to blocking in other regions, as it favors accelerated Greenland Ice Sheet melting and has substantial impacts on surface weather in adjacent regions, particularly in Europe and North America. Climate models notoriously underestimate the frequency of...
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ftdoajarticles:oai:doaj.org/article:1d9c4ff5c3754869b8d1ab841efb9a54 2024-09-15T18:08:28+00:00 Life cycle dynamics of Greenland blocking from a potential vorticity perspective S. Hauser F. Teubler M. Riemer P. Knippertz C. M. Grams 2024-04-01T00:00:00Z https://doi.org/10.5194/wcd-5-633-2024 https://doaj.org/article/1d9c4ff5c3754869b8d1ab841efb9a54 EN eng Copernicus Publications https://wcd.copernicus.org/articles/5/633/2024/wcd-5-633-2024.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-5-633-2024 2698-4016 https://doaj.org/article/1d9c4ff5c3754869b8d1ab841efb9a54 Weather and Climate Dynamics, Vol 5, Pp 633-658 (2024) Meteorology. Climatology QC851-999 article 2024 ftdoajarticles https://doi.org/10.5194/wcd-5-633-2024 2024-08-05T17:49:32Z Blocking over Greenland stands out in comparison to blocking in other regions, as it favors accelerated Greenland Ice Sheet melting and has substantial impacts on surface weather in adjacent regions, particularly in Europe and North America. Climate models notoriously underestimate the frequency of blocking over Greenland in historical periods, but the reasons for this are not entirely clear, as we are still lacking a full dynamical understanding of Greenland blocking from formation through maintenance to decay. This study investigates the dynamics of blocking life cycles over Greenland based on ERA5 reanalysis data from 1979–2021. A year-round weather regime definition allows us to identify Greenland blocking as consistent life cycles with an objective onset, maximum, and decay stage. By applying a new quasi-Lagrangian potential vorticity (PV) perspective, following the negative, upper-tropospheric PV anomalies (PVAs − ) associated with the block, we examine and quantify the contribution from different physical processes, including dry and moist dynamics, to the evolution of the PVA − amplitude. We find that PVAs − linked to blocking do not form locally over Greenland but propagate into the region along two distinct pathways (termed “upstream” and “retrogression”) during the days before the onset. The development of PVAs − differs more between the pathways than between seasons. Moist processes play a key role in the amplification of PVAs − before the onset and are linked to midlatitude warm conveyor belts. Interestingly, we find moist processes supporting the westward propagation of retrograding PVAs − from Europe, too, previously thought to be a process dominated by dry-barotropic Rossby wave propagation. After onset, moist processes remain the main contribution to PVA − amplification and maintenance. However, moist processes weaken markedly after the maximum stage, and dry processes, i.e., barotropic, nonlinear wave dynamics, dominate the decay of the PVAs − accompanied by a general decrease in blocking area. ... Article in Journal/Newspaper Greenland Ice Sheet Directory of Open Access Journals: DOAJ Articles Weather and Climate Dynamics 5 2 633 658 |
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Meteorology. Climatology QC851-999 |
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Meteorology. Climatology QC851-999 S. Hauser F. Teubler M. Riemer P. Knippertz C. M. Grams Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
topic_facet |
Meteorology. Climatology QC851-999 |
description |
Blocking over Greenland stands out in comparison to blocking in other regions, as it favors accelerated Greenland Ice Sheet melting and has substantial impacts on surface weather in adjacent regions, particularly in Europe and North America. Climate models notoriously underestimate the frequency of blocking over Greenland in historical periods, but the reasons for this are not entirely clear, as we are still lacking a full dynamical understanding of Greenland blocking from formation through maintenance to decay. This study investigates the dynamics of blocking life cycles over Greenland based on ERA5 reanalysis data from 1979–2021. A year-round weather regime definition allows us to identify Greenland blocking as consistent life cycles with an objective onset, maximum, and decay stage. By applying a new quasi-Lagrangian potential vorticity (PV) perspective, following the negative, upper-tropospheric PV anomalies (PVAs − ) associated with the block, we examine and quantify the contribution from different physical processes, including dry and moist dynamics, to the evolution of the PVA − amplitude. We find that PVAs − linked to blocking do not form locally over Greenland but propagate into the region along two distinct pathways (termed “upstream” and “retrogression”) during the days before the onset. The development of PVAs − differs more between the pathways than between seasons. Moist processes play a key role in the amplification of PVAs − before the onset and are linked to midlatitude warm conveyor belts. Interestingly, we find moist processes supporting the westward propagation of retrograding PVAs − from Europe, too, previously thought to be a process dominated by dry-barotropic Rossby wave propagation. After onset, moist processes remain the main contribution to PVA − amplification and maintenance. However, moist processes weaken markedly after the maximum stage, and dry processes, i.e., barotropic, nonlinear wave dynamics, dominate the decay of the PVAs − accompanied by a general decrease in blocking area. ... |
format |
Article in Journal/Newspaper |
author |
S. Hauser F. Teubler M. Riemer P. Knippertz C. M. Grams |
author_facet |
S. Hauser F. Teubler M. Riemer P. Knippertz C. M. Grams |
author_sort |
S. Hauser |
title |
Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
title_short |
Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
title_full |
Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
title_fullStr |
Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
title_full_unstemmed |
Life cycle dynamics of Greenland blocking from a potential vorticity perspective |
title_sort |
life cycle dynamics of greenland blocking from a potential vorticity perspective |
publisher |
Copernicus Publications |
publishDate |
2024 |
url |
https://doi.org/10.5194/wcd-5-633-2024 https://doaj.org/article/1d9c4ff5c3754869b8d1ab841efb9a54 |
genre |
Greenland Ice Sheet |
genre_facet |
Greenland Ice Sheet |
op_source |
Weather and Climate Dynamics, Vol 5, Pp 633-658 (2024) |
op_relation |
https://wcd.copernicus.org/articles/5/633/2024/wcd-5-633-2024.pdf https://doaj.org/toc/2698-4016 doi:10.5194/wcd-5-633-2024 2698-4016 https://doaj.org/article/1d9c4ff5c3754869b8d1ab841efb9a54 |
op_doi |
https://doi.org/10.5194/wcd-5-633-2024 |
container_title |
Weather and Climate Dynamics |
container_volume |
5 |
container_issue |
2 |
container_start_page |
633 |
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658 |
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1810445833434300416 |