Atmospheric boundary layers in Antarctica : observation and numerical simulation
Except during a few summer afternoon hours, the snow-covered surface of Antarctica is constantly cooling because of radiative processes. This results in a stable, persisting stratification of the atmospheric boundary layer that feeds katabatic winds along the slopes descending from the Plateau to th...
Main Author: | |
---|---|
Other Authors: | , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
Published: |
HAL CCSD
2014
|
Subjects: | |
Online Access: | https://theses.hal.science/tel-01228081 https://theses.hal.science/tel-01228081/document https://theses.hal.science/tel-01228081/file/BARRAL_2014_archivage.pdf |
id |
ftunivsavoie:oai:HAL:tel-01228081v1 |
---|---|
record_format |
openpolar |
institution |
Open Polar |
collection |
Université Savoie Mont Blanc: HAL |
op_collection_id |
ftunivsavoie |
language |
French |
topic |
Antarctica Stable boundary layers Turbulence Katabatic wind Numerical Modelling Observations Antarctique Couches limites stables Vent catabatique Modélisation numérique Observation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
spellingShingle |
Antarctica Stable boundary layers Turbulence Katabatic wind Numerical Modelling Observations Antarctique Couches limites stables Vent catabatique Modélisation numérique Observation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere Barral, Hélène Atmospheric boundary layers in Antarctica : observation and numerical simulation |
topic_facet |
Antarctica Stable boundary layers Turbulence Katabatic wind Numerical Modelling Observations Antarctique Couches limites stables Vent catabatique Modélisation numérique Observation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere |
description |
Except during a few summer afternoon hours, the snow-covered surface of Antarctica is constantly cooling because of radiative processes. This results in a stable, persisting stratification of the atmospheric boundary layer that feeds katabatic winds along the slopes descending from the Plateau to the Ocean. Temperature inversions and wind speeds both peak during the winter, with inversions regularly reaching 25 degrees (C) over the Plateau and winds exceeding 200,km/h along the coast. In the summer, significant inversions remain at night but solar heating leads to the formation of convective layers near the surface in the afternoon. With berms and large, empty slopes constantly covered with snow, Antarctica is a unique and perfect laboratory for the study of transitions between turbulent regimes and of the turbulence within stable and katabatic boundary layers. The investigation of these processes is usually made difficult by their sensitivity to heterogeneities at the surface. This thesis work documents three typical "text-book" summer cases: the diurnal cycle on the Antarctic Plateau, the generation of a local katabatic wind and the katabatic forcing of the boundary layer. The investigation of these three cases uses in-situ data. For two of these cases, the observational data has fed and been completed with some Meso-NH model simulation outputs. The first case focusses on the diurnal cycle at Dome C. On the Antarctic Plateau, Dome C is a flat, homogeneous area far from oceanic perturbations. Since a few years, a 45 meters tower samples the boundary layer there. In the summer, the diurnal cycle there is characterized by clean signals in both temperature and winds, with a nocturnal low-level jet within the boundary layer. A two-days data set representative of the rest of the summer has been selected for analysis and is used in the GABLS4 comparison study prepared in collaboration with Meteo France. Single-column simulations have been run for this comparison work launched in June. The second case examines a local ... |
author2 |
Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université de Grenoble Christophe Genthon Christophe Brun |
format |
Doctoral or Postdoctoral Thesis |
author |
Barral, Hélène |
author_facet |
Barral, Hélène |
author_sort |
Barral, Hélène |
title |
Atmospheric boundary layers in Antarctica : observation and numerical simulation |
title_short |
Atmospheric boundary layers in Antarctica : observation and numerical simulation |
title_full |
Atmospheric boundary layers in Antarctica : observation and numerical simulation |
title_fullStr |
Atmospheric boundary layers in Antarctica : observation and numerical simulation |
title_full_unstemmed |
Atmospheric boundary layers in Antarctica : observation and numerical simulation |
title_sort |
atmospheric boundary layers in antarctica : observation and numerical simulation |
publisher |
HAL CCSD |
publishDate |
2014 |
url |
https://theses.hal.science/tel-01228081 https://theses.hal.science/tel-01228081/document https://theses.hal.science/tel-01228081/file/BARRAL_2014_archivage.pdf |
genre |
Antarc* Antarctic Antarctica Antarctique* |
genre_facet |
Antarc* Antarctic Antarctica Antarctique* |
op_source |
https://theses.hal.science/tel-01228081 Océan, Atmosphère. Université de Grenoble, 2014. Français. ⟨NNT : 2014GRENU053⟩ |
op_relation |
NNT: 2014GRENU053 tel-01228081 https://theses.hal.science/tel-01228081 https://theses.hal.science/tel-01228081/document https://theses.hal.science/tel-01228081/file/BARRAL_2014_archivage.pdf |
op_rights |
info:eu-repo/semantics/OpenAccess |
_version_ |
1797570605649756160 |
spelling |
ftunivsavoie:oai:HAL:tel-01228081v1 2024-04-28T07:58:37+00:00 Atmospheric boundary layers in Antarctica : observation and numerical simulation Couches limites atmosphériques en Antarctique : observation et simulation numérique Barral, Hélène Laboratoire de glaciologie et géophysique de l'environnement (LGGE) Observatoire des Sciences de l'Univers de Grenoble (OSUG) Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) Université de Grenoble Christophe Genthon Christophe Brun 2014-11-26 https://theses.hal.science/tel-01228081 https://theses.hal.science/tel-01228081/document https://theses.hal.science/tel-01228081/file/BARRAL_2014_archivage.pdf fr fre HAL CCSD NNT: 2014GRENU053 tel-01228081 https://theses.hal.science/tel-01228081 https://theses.hal.science/tel-01228081/document https://theses.hal.science/tel-01228081/file/BARRAL_2014_archivage.pdf info:eu-repo/semantics/OpenAccess https://theses.hal.science/tel-01228081 Océan, Atmosphère. Université de Grenoble, 2014. Français. ⟨NNT : 2014GRENU053⟩ Antarctica Stable boundary layers Turbulence Katabatic wind Numerical Modelling Observations Antarctique Couches limites stables Vent catabatique Modélisation numérique Observation [SDU.OCEAN]Sciences of the Universe [physics]/Ocean Atmosphere info:eu-repo/semantics/doctoralThesis Theses 2014 ftunivsavoie 2024-04-11T01:01:27Z Except during a few summer afternoon hours, the snow-covered surface of Antarctica is constantly cooling because of radiative processes. This results in a stable, persisting stratification of the atmospheric boundary layer that feeds katabatic winds along the slopes descending from the Plateau to the Ocean. Temperature inversions and wind speeds both peak during the winter, with inversions regularly reaching 25 degrees (C) over the Plateau and winds exceeding 200,km/h along the coast. In the summer, significant inversions remain at night but solar heating leads to the formation of convective layers near the surface in the afternoon. With berms and large, empty slopes constantly covered with snow, Antarctica is a unique and perfect laboratory for the study of transitions between turbulent regimes and of the turbulence within stable and katabatic boundary layers. The investigation of these processes is usually made difficult by their sensitivity to heterogeneities at the surface. This thesis work documents three typical "text-book" summer cases: the diurnal cycle on the Antarctic Plateau, the generation of a local katabatic wind and the katabatic forcing of the boundary layer. The investigation of these three cases uses in-situ data. For two of these cases, the observational data has fed and been completed with some Meso-NH model simulation outputs. The first case focusses on the diurnal cycle at Dome C. On the Antarctic Plateau, Dome C is a flat, homogeneous area far from oceanic perturbations. Since a few years, a 45 meters tower samples the boundary layer there. In the summer, the diurnal cycle there is characterized by clean signals in both temperature and winds, with a nocturnal low-level jet within the boundary layer. A two-days data set representative of the rest of the summer has been selected for analysis and is used in the GABLS4 comparison study prepared in collaboration with Meteo France. Single-column simulations have been run for this comparison work launched in June. The second case examines a local ... Doctoral or Postdoctoral Thesis Antarc* Antarctic Antarctica Antarctique* Université Savoie Mont Blanc: HAL |