A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic
Low-level jets (LLJs) are climatological features in polar regions. It is well known that katabatic winds over the slopes of the Antarctic ice sheet are associated with strong LLJs. Barrier winds occurring, e.g., along the Antarctic Peninsula may also show LLJ structures. A few observational studies...
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ftmdpi:oai:mdpi.com:/2073-4433/12/12/1635/ 2023-08-20T04:02:24+02:00 A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic Günther Heinemann Rolf Zentek agris 2021-12-07 application/pdf https://doi.org/10.3390/atmos12121635 EN eng Multidisciplinary Digital Publishing Institute Atmospheric Techniques, Instruments, and Modeling https://dx.doi.org/10.3390/atmos12121635 https://creativecommons.org/licenses/by/4.0/ Atmosphere; Volume 12; Issue 12; Pages: 1635 Antarctic stable boundary layer low-level jets inversion katabatic winds Text 2021 ftmdpi https://doi.org/10.3390/atmos12121635 2023-08-01T03:28:42Z Low-level jets (LLJs) are climatological features in polar regions. It is well known that katabatic winds over the slopes of the Antarctic ice sheet are associated with strong LLJs. Barrier winds occurring, e.g., along the Antarctic Peninsula may also show LLJ structures. A few observational studies show that LLJs occur over sea ice regions. We present a model-based climatology of the wind field, of low-level inversions and of LLJs in the Weddell Sea region of the Antarctic for the period 2002–2016. The sensitivity of the LLJ detection on the selection of the wind speed maximum is investigated. The common criterion of an anomaly of at least 2 m/s is extended to a relative criterion of wind speed decrease above and below the LLJ. The frequencies of LLJs are sensitive to the choice of the relative criterion, i.e., if the value for the relative decrease exceeds 15%. The LLJs are evaluated with respect to the frequency distributions of height, speed, directional shear and stability for different regions. LLJs are most frequent in the katabatic wind regime over the ice sheet and in barrier wind regions. During winter, katabatic LLJs occur with frequencies of more than 70% in many areas. Katabatic LLJs show a narrow range of heights (mostly below 200 m) and speeds (typically 10–20 m/s), while LLJs over the sea ice cover a broad range of speeds and heights. LLJs are associated with surface inversions or low-level lifted inversions. LLJs in the katabatic wind and barrier wind regions can last several days during winter. The duration of LLJs is sensitive to the LLJ definition criteria. We propose to use only the absolute criterion for model studies. Text Antarc* Antarctic Antarctic Peninsula Ice Sheet Sea ice Weddell Sea MDPI Open Access Publishing Antarctic Antarctic Peninsula The Antarctic Weddell Weddell Sea Atmosphere 12 12 1635 |
institution |
Open Polar |
collection |
MDPI Open Access Publishing |
op_collection_id |
ftmdpi |
language |
English |
topic |
Antarctic stable boundary layer low-level jets inversion katabatic winds |
spellingShingle |
Antarctic stable boundary layer low-level jets inversion katabatic winds Günther Heinemann Rolf Zentek A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
topic_facet |
Antarctic stable boundary layer low-level jets inversion katabatic winds |
description |
Low-level jets (LLJs) are climatological features in polar regions. It is well known that katabatic winds over the slopes of the Antarctic ice sheet are associated with strong LLJs. Barrier winds occurring, e.g., along the Antarctic Peninsula may also show LLJ structures. A few observational studies show that LLJs occur over sea ice regions. We present a model-based climatology of the wind field, of low-level inversions and of LLJs in the Weddell Sea region of the Antarctic for the period 2002–2016. The sensitivity of the LLJ detection on the selection of the wind speed maximum is investigated. The common criterion of an anomaly of at least 2 m/s is extended to a relative criterion of wind speed decrease above and below the LLJ. The frequencies of LLJs are sensitive to the choice of the relative criterion, i.e., if the value for the relative decrease exceeds 15%. The LLJs are evaluated with respect to the frequency distributions of height, speed, directional shear and stability for different regions. LLJs are most frequent in the katabatic wind regime over the ice sheet and in barrier wind regions. During winter, katabatic LLJs occur with frequencies of more than 70% in many areas. Katabatic LLJs show a narrow range of heights (mostly below 200 m) and speeds (typically 10–20 m/s), while LLJs over the sea ice cover a broad range of speeds and heights. LLJs are associated with surface inversions or low-level lifted inversions. LLJs in the katabatic wind and barrier wind regions can last several days during winter. The duration of LLJs is sensitive to the LLJ definition criteria. We propose to use only the absolute criterion for model studies. |
format |
Text |
author |
Günther Heinemann Rolf Zentek |
author_facet |
Günther Heinemann Rolf Zentek |
author_sort |
Günther Heinemann |
title |
A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
title_short |
A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
title_full |
A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
title_fullStr |
A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
title_full_unstemmed |
A Model-Based Climatology of Low-Level Jets in the Weddell Sea Region of the Antarctic |
title_sort |
model-based climatology of low-level jets in the weddell sea region of the antarctic |
publisher |
Multidisciplinary Digital Publishing Institute |
publishDate |
2021 |
url |
https://doi.org/10.3390/atmos12121635 |
op_coverage |
agris |
geographic |
Antarctic Antarctic Peninsula The Antarctic Weddell Weddell Sea |
geographic_facet |
Antarctic Antarctic Peninsula The Antarctic Weddell Weddell Sea |
genre |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Sea ice Weddell Sea |
genre_facet |
Antarc* Antarctic Antarctic Peninsula Ice Sheet Sea ice Weddell Sea |
op_source |
Atmosphere; Volume 12; Issue 12; Pages: 1635 |
op_relation |
Atmospheric Techniques, Instruments, and Modeling https://dx.doi.org/10.3390/atmos12121635 |
op_rights |
https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.3390/atmos12121635 |
container_title |
Atmosphere |
container_volume |
12 |
container_issue |
12 |
container_start_page |
1635 |
_version_ |
1774712841878634496 |