|   | 
Details
   web
Records
Author Vignon Etienne, van de Wiel Bas J. H., van Hooijdonk Ivo G. S., Genthon Christophe, van der Linden Steven J. A., van Hooft J. Antoon, Baas Peter, Maurel William, Traullé Olivier, Casasanta Giampietro
Title Stable boundary‐layer regimes at Dome C, Antarctica: observation and analysis Type Journal
Year 2017 Publication Quarterly journal of the royal meteorological society Abbreviated Journal
Volume 143 Issue 704 Pages 1241-1253
Keywords Antarctic atmosphere critical transition stable boundary layer wind‐speed threshold
Abstract Investigation of meteorological measurements along a 45 m tower at Dome C on the high East Antarctic Plateau revealed two distinct stable boundary layer (SBL) regimes at this location. The first regime is characterized by strong winds and continuous turbulence. It results in full vertical coupling of temperature, wind magnitude and wind direction in the SBL. The second regime is characterized by weak winds, associated with weak turbulent activity and very strong temperature inversions reaching up to 25 K in the lowest 10 m. Vertical temperature profiles are generally exponentially shaped (convex) in the first regime and ?convex?concave?convex? in the second. The transition between the two regimes is particularly abrupt when looking at the near?surface temperature inversion and it can be identified by a 10 m wind?speed threshold. With winds under this threshold, the turbulent heat supply toward the surface becomes significantly lower than the net surface radiative cooling. The threshold value (including its range of uncertainty) appears to agree with recent theoretical predictions from the so?called ?minimum wind speed for sustainable turbulence? (MWST) theory. For the quasi?steady, clear?sky winter cases, the relation between the near?surface inversion amplitude and the wind speed takes a characteristic ?S? shape. Closer analysis suggests that this relation corresponds to a ?critical transition? between a steady turbulent and a steady ?radiative? regime, with a dynamically unstable branch in the transition zone. These fascinating characteristics of the Antarctic boundary layer challenge present and future numerical models to represent this region in a physically correct manner.
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-9009 ISBN 0035-9009 Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6574
Permanent link to this record
 

 
Author Camille reverchon
Title Etude des précipitations à Dome C sur le plateau antarctique Type Master 1
Year 2017 Publication Master's report, sciences de la terre et des planètes, environnement, université grenoble alpes. Abbreviated Journal
Volume Issue Pages
Keywords
Abstract Although antarcic precipitation has been studied for about half a century, the rate and occurrence of precipitation on the Antarctic Plateau are still unknown. During the summer campaign 2015-2016, a TPS-3100 (or Hotplate) precipitation gauge was set-up at Dome C to test the ability of such an instrument to measure precipitation in the climate conditions of the Antarctic Plateau. The TPS-3100 consists of two identical heated and thermally insulated aluminium disc plates. One of the plates faces up and measures the rate of precipitation, the other faces down and serves as a reference. The two plates are heated independently and maintained at a constant temperature of 75 ° C. An analysis of the data collected by the TPS-3100 and a characterization of the precipitation events at Dome C over the year 2016 were carried out in this study. Hotplate’s measurements have been found to generally disagree with ECMWF interim analyses and reanalyses and LMDZ simulations, not only in terms of quantity but also occurrence. However, it remains difficult to disentangle between errors in the measurements and those in the other datasets since there is no benchmark data set for precipitation rates at Dome C.
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6583
Permanent link to this record
 

 
Author Genthon C., L. Piard, E. Vignon, J.-b. Madeleine, M. Casado, And H. Gallée
Title Atmospheric moisture supersaturations in the near-surface atmosphere of Dome C, Antarctic Plateau Type Conference - International - Communication
Year 2017 Publication EGU 2017, 23-28 April, 2017 Vienna, Austria Abbreviated Journal
Volume Issue Pages
Keywords
Abstract
Programme (up) 1013
Campaign
Address
Corporate Author Thesis Bachelor's thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6676
Permanent link to this record
 

 
Author Vignon E., F. Hourdin, C. Genthon, J.-b. Madeleine, F. Cheruy, H. Gallée, E. Bazile, M.-p. Lefebvre, And B. J. H. Van De Wiel.
Title The Ability of a General Circulation Model to represent the Atmospheric Boundary Layer over the Antarctic Plateau Type Conference - International - Communication
Year 2017 Publication EGU 2017, 23-28 April, 2017 Vienna, Austria Abbreviated Journal
Volume Issue Pages
Keywords
Abstract
Programme (up) 1013
Campaign
Address
Corporate Author Thesis Bachelor's thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6677
Permanent link to this record
 

 
Author Madeleine J.-b., C. Genthon, E. Vignon, F. Hourdin, F. Lemonnier, H. Gallée, And L. Piard
Title Measuring and Modeling Ice Supersaturation at Dome C Type Communication
Year 2017 Publication 12th workshop on antarctic meteorlogy and climate, boulder, co, usa, 28-29 juin 2017 Abbreviated Journal
Volume Issue Pages
Keywords
Abstract
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6678
Permanent link to this record
 

 
Author Florentin Lemonnier, Jean-Baptiste Madeleine, Chantal Claud, Christophe Genthon, Claudio Durán-Alarcón, Cyril Palerme, Alexis Berne, Niels Souverijns, Nicole van Lipzig, Irina V. Gorodetskaya, Tristan L'Ecuyer, Norman Wood
Title Evaluation of CloudSat snowfall rate profiles by a comparison with in situ micro-rain radar observations in East Antarctica Type Journal
Year 2019 Publication The Cryosphere Abbreviated Journal
Volume 13 Issue 3 Pages 943-954
Keywords
Abstract

Abstract. The Antarctic continent is a vast desert and is the coldest and the most unknown area on Earth. It contains the Antarctic ice sheet, the largest continental water reservoir on Earth that could be affected by the current global warming, leading to sea level rise. The only significant supply of ice is through precipitation, which can be observed from the surface and from space. Remote-sensing observations of the coastal regions and the inner continent using CloudSat radar give an estimated rate of snowfall but with uncertainties twice as large as each single measured value, whereas climate models give a range from half to twice the space–time-averaged observations. The aim of this study is the evaluation of the vertical precipitation rate profiles of CloudSat radar by comparison with two surface-based micro-rain radars (MRRs), located at the coastal French Dumont d'Urville station and at the Belgian Princess Elisabeth station located in the Dronning Maud Land escarpment zone. This in turn leads to a better understanding and reassessment of CloudSat uncertainties. We compared a total of four precipitation events, two per station, when CloudSat overpassed within 10 km of the station and we compared these two different datasets at each vertical level. The correlation between both datasets is near-perfect, even though climatic and geographic conditions are different for the two stations. Using different CloudSat and MRR vertical levels, we obtain 10 km space-scale and short-timescale (a few seconds) CloudSat uncertainties from −13 % up to +22 %. This confirms the robustness of the CloudSat retrievals of snowfall over Antarctica above the blind zone and justifies further analyses of this dataset.

Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1994-0416 ISBN 1994-0416 Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 6905
Permanent link to this record
 

 
Author Souverijns, N., A. Gossart, S. Lhermitte, I. V. Gorodetskaya, J. Grazioli, A. Berne, C. Durán-alarcón, B. Boudevillain, C. Genthon, C. Scarchilli, And N. P. M. Van Lipzig
Title Evaluation of the CloudSat surface snowfall product over Antarctica using ground-based precipitation radars Type Journal
Year 2018 Publication The cryosphere Abbreviated Journal
Volume 12 Issue Pages 3775-3789
Keywords
Abstract
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1994-0416 ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 7405
Permanent link to this record
 

 
Author Etienne Vignon, Frédéric Hourdin, Christophe Genthon, Bas J. H. Van de Wiel, Hubert Gallée, Jean-Baptiste Madeleine, Julien Beaumet
Title Modeling the Dynamics of the Atmospheric Boundary Layer Over the Antarctic Plateau With a General Circulation Model Type Journal
Year 2017 Publication Journal of Advances in Modeling Earth Systems Abbreviated Journal
Volume 10 Issue 1 Pages 98-125
Keywords Antarctic Plateau boundary-layer general circulation model LMDZ stable boundary-layer regimes
Abstract Abstract Observations evidence extremely stable boundary layers (SBL) over the Antarctic Plateau and sharp regime transitions between weakly and very stable conditions. Representing such features is a challenge for climate models. This study assesses the modeling of the dynamics of the boundary layer over the Antarctic Plateau in the LMDZ general circulation model. It uses 1 year simulations with a stretched-grid over Dome C. The model is nudged with reanalyses outside of the Dome C region such as simulations can be directly compared to in situ observations. We underline the critical role of the downward longwave radiation for modeling the surface temperature. LMDZ reasonably represents the near-surface seasonal profiles of wind and temperature but strong temperature inversions are degraded by enhanced turbulent mixing formulations. Unlike ERA-Interim reanalyses, LMDZ reproduces two SBL regimes and the regime transition, with a sudden increase in the near-surface inversion with decreasing wind speed. The sharpness of the transition depends on the stability function used for calculating the surface drag coefficient. Moreover, using a refined vertical grid leads to a better reversed ?S-shaped? relationship between the inversion and the wind. Sudden warming events associated to synoptic advections of warm and moist air are also well reproduced. Near-surface supersaturation with respect to ice is not allowed in LMDZ but the impact on the SBL structure is moderate. Finally, climate simulations with the free model show that the recommended configuration leads to stronger inversions and winds over the ice-sheet. However, the near-surface wind remains underestimated over the slopes of East-Antarctica.
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1942-2466 ISBN 1942-2466 Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 7195
Permanent link to this record
 

 
Author Etienne Vignon, Frédéric Hourdin, Christophe Genthon, Hubert Gallée, Eric Bazile, Marie-Pierre Lefebvre, Jean-Baptiste Madeleine, Bas J. H. Van de Wiel
Title Antarctic boundary layer parametrization in a general circulation model: 1-D simulations facing summer observations at Dome C Type Journal
Year 2017 Publication Journal of Geophysical Research: Atmospheres Abbreviated Journal
Volume 122 Issue 13 Pages 6818-6843
Keywords Antarctic Plateau atmospheric boundary layer GABLS4 general circulation model physical parametrizations
Abstract The parametrization of the atmospheric boundary layer (ABL) is critical over the Antarctic Plateau for climate modelling since it affects the climatological temperature inversion and the negatively buoyant near-surface flow over the ice-sheet. This study challenges state-of-the-art parametrizations used in general circulation models to represent the clear-sky summertime diurnal cycle of the ABL at Dome C, Antarctic Plateau. The Laboratoire de Météorologie Dynamique-Zoom model is run in a 1-D configuration on the fourth Global Energy and Water Cycle Exchanges Project Atmospheric Boundary Layers Study case. Simulations are analyzed and compared to observations, giving insights into the sensitivity of one model that participates to the intercomparison exercise. Snow albedo and thermal inertia are calibrated leading to better surface temperatures. Using the so-called “thermal plume model” improves the momentum mixing in the diurnal ABL. In stable conditions, four turbulence schemes are tested. Best simulations are those in which the turbulence cuts off above 35 m in the middle of the night, highlighting the contribution of the longwave radiation in the ABL heat budget. However, the nocturnal surface layer is not stable enough to distinguish between surface fluxes computed with different stability functions. The absence of subsidence in the forcings and an underestimation of downward longwave radiation are identified to be likely responsible for a cold bias in the nocturnal ABL. Apart from model-specific improvements, the paper clarifies on which are the critical aspects to improve in general circulation models to correctly represent the summertime ABL over the Antarctic Plateau.
Programme (up) 1013
Campaign
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-8996 ISBN 2169-8996 Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 7196
Permanent link to this record
 

 
Author Etienne Vignon
Title The extreme atmospheric boundary layer over the Antarctic Plateau and its representation in climate models Type Thesis
Year 2017 Publication Abbreviated Journal
Volume Issue Pages
Keywords
Abstract L’observation des couches limites atmosphériques au dessus du plateau antarctique a mis en évidence les plus fortes inversions de température proches de la surface de la planète. Bien paramétriser ces couches limites extrêmes dans un modèle de circulation générale est essentiel pour represéntercorrectement l’inversion climatologique de température au dessus du plateau, mais également pour reproduire des vents catabatiques réalistes en aval du plateau et de surcroit, une circulation atmosphérique correcte dans l’hémisphère sud. Les conclusions des précédentes “Gewex AtmosphericBoundary Layer Studies” (GABLS) ont conduit au constat que la paramétrisation des couches limites stables dans les modèles climatiques est une des priorités pour la communauté des modélisateurs.Ceci est dû au fait que la nature même des processus physiques en jeu est mal connue mais aussi parce que les lois de similitudes, sur lesquelles les paramétrisations du mélange turbulent sont fondées, ne sont pas applicables en condition très stable. L’objectif de ces travaux de thèse est d’évaluer et d’améliorer la représentation des couches limites sur le plateau antarctique dans le modèle français de circulation générale Laboratoire de MétéorologieDynamique-Zoom (LMDZ), composante atmosphérique du modèle de climat IPSL. Avant l’évaluation même du modèle, une étude approfondie de la couche limite de surface et de la structure de la couche limite stable a été conduite à partir de l’analyse de mesures in situ au Dôme C. Il en a résulté une caractérisation de la hauteur de rugosité aérodynamique, une estimation des flux turbulents de surface sur une année entière ainsi que la mise en évidence de sursaturations de la vapeur d’eau par rapport à la glace. L’analyse des mesures de température et de vent le long d’une tour de 45 m a aussi montré que la couche limite se comporte tel un système dynamique à deux régimes distincts. La relation entrevitesse du vent et inversion de température décrit un “S renversé”, suggérant une transition de régime suivant un hystérésis. Une étude complémentaire a révélé que ce comportement dynamique à deux régimes est une caractéristique générale et robuste des couches limites stables, qui peuvent transiter,selon l’intensité des forçages, d’un régime ’turbulent’ peu stable à un régime ’radiatif’ très stable et vice et versa.Le modèle LMDZ a ensuite été évalué en configuration 1D sur un cycle diurne d’été dans le cadre de la quatrième expérience GABLS. Des tests de sensibilité aux paramètres de surface et à la paramétrisation du mélange turbulent ont été réalisés. Ils ont conduit à de nettes améliorations des performancesdu modèle ainsi qu’à la mise en place d’une configuration adaptée aux conditions antarctiques. Des simulations complémentaires en 3D ont par la suite soulevé l’importance du transfert radiatif infrarouge et de la paramétrisation des flux turbulents de surface pour la modélisation de la couchelimite sur le plateau pendant la nuit polaire. Enfin, les travaux de thèse ont été étendus à la modélisation des couches limites stables continentales. Les paramétrisations locales de turbulence ont en effet tendance à sous-estimer le mélange sous-maille continental, en raison de la multitude des processusde mélange en jeu. Un réflexion a donc été portée sur la façon de palier ce manque de mélange, avec comme idée directrice de transférer la perte d’énergie cinétique grande échelle perdue lors du freinage de l’écoulement par les ondes de gravité, vers de l’énergie cinétique turbulente.
Programme (up) 1013
Campaign
Address
Corporate Author Thesis Bachelor's thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes Approved yes
Call Number Serial 7930
Permanent link to this record