Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica
International audience The offshore extent of Antarctic katabatic winds exerts a strong control on the production of sea ice and the formation of polynyas. In this study, we make use of a combination of ground-based remotely sensed and meteorological measurements at Dumont d'Urville (DDU) stati...
Published in: | Journal of the Atmospheric Sciences |
---|---|
Main Authors: | , , , , , |
Other Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
HAL CCSD
2020
|
Subjects: | |
Online Access: | https://hal.science/hal-03065736 https://hal.science/hal-03065736/document https://hal.science/hal-03065736/file/jasd190264.pdf https://doi.org/10.1175/JAS-D-19-0264.1 |
id |
ftunigrenoble:oai:HAL:hal-03065736v1 |
---|---|
record_format |
openpolar |
spelling |
ftunigrenoble:oai:HAL:hal-03065736v1 2024-05-12T07:55:09+00:00 Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica Vignon, Étienne Picard, Ghislain Durán-Alarcón, Claudio Alexander, Simon Gallée, Hubert Berne, Alexis Centre National de la Recherche Scientifique (CNRS) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) 2020-04-01 https://hal.science/hal-03065736 https://hal.science/hal-03065736/document https://hal.science/hal-03065736/file/jasd190264.pdf https://doi.org/10.1175/JAS-D-19-0264.1 en eng HAL CCSD American Meteorological Society info:eu-repo/semantics/altIdentifier/doi/10.1175/JAS-D-19-0264.1 hal-03065736 https://hal.science/hal-03065736 https://hal.science/hal-03065736/document https://hal.science/hal-03065736/file/jasd190264.pdf doi:10.1175/JAS-D-19-0264.1 info:eu-repo/semantics/OpenAccess ISSN: 0022-4928 EISSN: 1520-0469 Journal of the Atmospheric Sciences https://hal.science/hal-03065736 Journal of the Atmospheric Sciences, 2020, 77 (4), pp.1295-1312. ⟨10.1175/JAS-D-19-0264.1⟩ [SDE]Environmental Sciences info:eu-repo/semantics/article Journal articles 2020 ftunigrenoble https://doi.org/10.1175/JAS-D-19-0264.1 2024-04-18T03:23:33Z International audience The offshore extent of Antarctic katabatic winds exerts a strong control on the production of sea ice and the formation of polynyas. In this study, we make use of a combination of ground-based remotely sensed and meteorological measurements at Dumont d'Urville (DDU) station, satellite images, and simulations with the Weather Research and Forecasting Model to analyze a major katabatic wind event in Adélie Land. Once well developed over the slope of the ice sheet, the katabatic flow experiences an abrupt transition near the coastal edge consisting of a sharp increase in the boundary layer depth, a sudden decrease in wind speed, and a decrease in Froude number from 3.5 to 0.3. This so-called katabatic jump manifests as a turbulent ''wall'' of blowing snow in which updrafts exceed 5 m s 21. The wall reaches heights of 1000 m and its horizontal extent along the coast is more than 400 km. By destabilizing the boundary layer downstream, the jump favors the trapping of a gravity wave train-with a horizontal wavelength of 10.5 km-that develops in a few hours. The trapped gravity waves exert a drag that considerably slows down the low-level outflow. Moreover, atmospheric rotors form below the first wave crests. The wind speed record measured at DDU in 2017 (58.5 m s 21) is due to the vertical advection of momentum by a rotor. A statistical analysis of observations at DDU reveals that katabatic jumps and low-level trapped gravity waves occur frequently over coastal Adélie Land. It emphasizes the important role of such phenomena in the coastal Antarctic dynamics. Article in Journal/Newspaper Antarc* Antarctic Antarctica Ice Sheet Sea ice Université Grenoble Alpes: HAL Antarctic Dumont d'Urville ENVELOPE(140.017,140.017,-66.667,-66.667) Dumont-d'Urville ENVELOPE(140.013,140.013,-66.667,-66.667) Journal of the Atmospheric Sciences 77 4 1295 1312 |
institution |
Open Polar |
collection |
Université Grenoble Alpes: HAL |
op_collection_id |
ftunigrenoble |
language |
English |
topic |
[SDE]Environmental Sciences |
spellingShingle |
[SDE]Environmental Sciences Vignon, Étienne Picard, Ghislain Durán-Alarcón, Claudio Alexander, Simon Gallée, Hubert Berne, Alexis Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
topic_facet |
[SDE]Environmental Sciences |
description |
International audience The offshore extent of Antarctic katabatic winds exerts a strong control on the production of sea ice and the formation of polynyas. In this study, we make use of a combination of ground-based remotely sensed and meteorological measurements at Dumont d'Urville (DDU) station, satellite images, and simulations with the Weather Research and Forecasting Model to analyze a major katabatic wind event in Adélie Land. Once well developed over the slope of the ice sheet, the katabatic flow experiences an abrupt transition near the coastal edge consisting of a sharp increase in the boundary layer depth, a sudden decrease in wind speed, and a decrease in Froude number from 3.5 to 0.3. This so-called katabatic jump manifests as a turbulent ''wall'' of blowing snow in which updrafts exceed 5 m s 21. The wall reaches heights of 1000 m and its horizontal extent along the coast is more than 400 km. By destabilizing the boundary layer downstream, the jump favors the trapping of a gravity wave train-with a horizontal wavelength of 10.5 km-that develops in a few hours. The trapped gravity waves exert a drag that considerably slows down the low-level outflow. Moreover, atmospheric rotors form below the first wave crests. The wind speed record measured at DDU in 2017 (58.5 m s 21) is due to the vertical advection of momentum by a rotor. A statistical analysis of observations at DDU reveals that katabatic jumps and low-level trapped gravity waves occur frequently over coastal Adélie Land. It emphasizes the important role of such phenomena in the coastal Antarctic dynamics. |
author2 |
Centre National de la Recherche Scientifique (CNRS) Institut des Géosciences de l’Environnement (IGE) Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ) Université Grenoble Alpes (UGA) |
format |
Article in Journal/Newspaper |
author |
Vignon, Étienne Picard, Ghislain Durán-Alarcón, Claudio Alexander, Simon Gallée, Hubert Berne, Alexis |
author_facet |
Vignon, Étienne Picard, Ghislain Durán-Alarcón, Claudio Alexander, Simon Gallée, Hubert Berne, Alexis |
author_sort |
Vignon, Étienne |
title |
Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
title_short |
Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
title_full |
Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
title_fullStr |
Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
title_full_unstemmed |
Gravity Wave Excitation during the Coastal Transition of an Extreme Katabatic Flow in Antarctica |
title_sort |
gravity wave excitation during the coastal transition of an extreme katabatic flow in antarctica |
publisher |
HAL CCSD |
publishDate |
2020 |
url |
https://hal.science/hal-03065736 https://hal.science/hal-03065736/document https://hal.science/hal-03065736/file/jasd190264.pdf https://doi.org/10.1175/JAS-D-19-0264.1 |
long_lat |
ENVELOPE(140.017,140.017,-66.667,-66.667) ENVELOPE(140.013,140.013,-66.667,-66.667) |
geographic |
Antarctic Dumont d'Urville Dumont-d'Urville |
geographic_facet |
Antarctic Dumont d'Urville Dumont-d'Urville |
genre |
Antarc* Antarctic Antarctica Ice Sheet Sea ice |
genre_facet |
Antarc* Antarctic Antarctica Ice Sheet Sea ice |
op_source |
ISSN: 0022-4928 EISSN: 1520-0469 Journal of the Atmospheric Sciences https://hal.science/hal-03065736 Journal of the Atmospheric Sciences, 2020, 77 (4), pp.1295-1312. ⟨10.1175/JAS-D-19-0264.1⟩ |
op_relation |
info:eu-repo/semantics/altIdentifier/doi/10.1175/JAS-D-19-0264.1 hal-03065736 https://hal.science/hal-03065736 https://hal.science/hal-03065736/document https://hal.science/hal-03065736/file/jasd190264.pdf doi:10.1175/JAS-D-19-0264.1 |
op_rights |
info:eu-repo/semantics/OpenAccess |
op_doi |
https://doi.org/10.1175/JAS-D-19-0264.1 |
container_title |
Journal of the Atmospheric Sciences |
container_volume |
77 |
container_issue |
4 |
container_start_page |
1295 |
op_container_end_page |
1312 |
_version_ |
1798834561708195840 |