Joël Savarino, William C. Vicars, Michel Legrand, Suzanne Preunkert, Bruno Jourdain, Markus M. Frey, Alexandre Kukui, Nicolas Caillon, Jaime Gil Roca. (2016). Oxygen isotope mass balance of atmospheric nitrate at Dome C, East Antarctica, during the OPALE campaign (Vol. 16). Bachelor's thesis, , .
Abstract: Abstract. Variations In The Stable Oxygen Isotope Composition Of Atmospheric Nitrate Act As Novel Tools For Studying Oxidative Processes Taking Place In The Troposphere. They Provide Both Qualitative And Quantitative Constraints On The Pathways Determining The Fate Of Atmospheric Nitrogen Oxides (No + No2 = Nox). The Unique And Distinctive 17o Excess (Δ17o = δ17o − 0.52 × δ18o) Of Ozone, Which Is Transferred To Nox Via Oxidation, Is A Particularly Useful Isotopic Fingerprint In Studies Of Nox Transformations. Constraining The Propagation Of 17o Excess Within The Nox Cycle Is Critical In Polar Areas, Where There Exists The Possibility Of Extending Atmospheric Investigations To The Glacial–interglacial Timescale Using Deep Ice Core Records Of Nitrate. Here We Present Measurements Of The Comprehensive Isotopic Composition Of Atmospheric Nitrate Collected At Dome C (East Antarctic Plateau) During The Austral Summer Of 2011/2012. Nitrate Isotope Analysis Has Been Here Combined For The First Time With Key Precursors Involved In Nitrate Production (Nox, O3, Oh, Ho2, Ro2, Etc.) And Direct Observations Of The Transferrable Δ17o Of Surface Ozone, Which Was Measured At Dome C Throughout 2012 Using Our Recently Developed Analytical Approach. Assuming That Nitrate Is Mainly Produced In Antarctica In Summer Through The Oh + No2 Pathway And Using Concurrent Measurements Of Oh And No2, We Calculated A Δ17o Signature For Nitrate On The Order Of (21–22 ± 3) ‰. These Values Are Lower Than The Measured Values That Ranged Between 27 And 31 ‰. This Discrepancy Between Expected And Observed Δ17o(no3−) Values Suggests The Existence Of An Unknown Process That Contributes Significantly To The Atmospheric Nitrate Budget Over This East Antarctic Region. However, Systematic Errors Or False Isotopic Balance Transfer Functions Are Not Totally Excluded.
Programme: 1011,1149
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Genthon Christophe, Town Michael S, Six Delphine, Favier Vincent, Argentini Stefania, Pellegrini Andrea, . (2010). Meteorological atmospheric boundary layer measurements and ECMWF analyses during summer at Dome C, Antarctica
. J. Geophys. Res., 115(D5), D05104–.
Abstract: Six levels of meteorological sensors have been deployed along a 45 m tower at the French-Italian Concordia station, Dome C, Antarctic. We present measurements of vertical profiles, the diurnal cycle, and interdiurnal variability of temperature, humidity, and wind speed and direction for 3 weeks during the southern summer of 2008. These measurements are compared to 6-hourly European Center for Medium-Range Forecasts (ECMWF) analyses and daily radiosoundings. The ECMWF analyses show a 3–4C warm bias relative to the tower observations. They reproduce the diurnal cycle of temperature with slightly weaker amplitude and weaker vertical gradients. The amplitude of the diurnal cycle of relative humidity is overestimated by ECMWF because the amplitude of the absolute humidity diurnal cycle is too small. The nighttime surface-based wind shear and Ekman spiral is also not reproduced in the ECMWF analyses. Radiosonde temperatures are biased low relative to the tower observations in the lowest 30 m but approach agreement at the top of the tower. Prior to bias correction for age-related contamination, radiosonde relative humidities are biased low relative to the tower observations in the lowest 10 m but agree with tower observations above this height. After correction for the age-related bias, the radiosonde relative humidity agrees with tower observations below 10 m but is biased high above this height. Tower temperature observations may also be biased by solar heating, despite radiation shielding and natural ventilation.
Keywords: Antarctica, boundary layer, ECMWF, 3307 Atmospheric Processes: Boundary layer processes, 0798 Cryosphere: Modeling, 0394 Atmospheric Composition and Structure: Instruments and techniques,
Programme: 1013
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Rabier Florence, Bouchard Aurélie, Brun Eric, Doerenbecher Alexis, Guedj Stéphanie, Guidard Vincent, Karbou Fatima, Peuch Vincent-Henri, Amraoui Laaziz El, Puech Dominique, Genthon Christophe, Picard Ghislain, Town Michael, Hertzog Albert, Vial François, Cocquerez Philippe, Cohn Stephen A, Hock Terry, Fox Jack, Cole Hal, Parsons David, Powers Jordan, Romberg Keith, VanAndel Joseph, Deshler Terry, Mercer Jennifer, Haase Jennifer S, Avallone Linnea, Kalnajs Lars, Mechoso C Roberto, Tangborn Andrew, Pellegrini Andrea, Frenot Yves, Thépaut Jean-Noël, McNally Anthony, Balsamo Gianpaolo, Steinle Peter, . (2010). The Concordiasi Project in Antarctica
. BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY, 91(1), 69–85.
Abstract: Abstract The Concordiasi project is making innovative observations of the atmosphere above Antarctica. The most important goals of the Concordiasi are as follows: To enhance the accuracy of weather prediction and climate records in Antarctica through the assimilation of in situ and satellite data, with an emphasis on data provided by hyperspectral infrared sounders. The focus is on clouds, precipitation, and the mass budget of the ice sheets. The improvements in dynamical model analyses and forecasts will be used in chemical-transport models that describe the links between the polar vortex dynamics and ozone depletion, and to advance the understanding of the Earth system by examining the interactions between Antarctica and lower latitudes.To improve our understanding of microphysical and dynamical processes controlling the polar ozone, by providing the first quasi-Lagrangian observations of stratospheric ozone and particles, in addition to an improved characterization of the 3D polar vortex dynamics. Tech...
Programme: 1013
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Brandun M.
Genthon C. (2010). Studies of Antarctic precipitation statistics.
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Genthon, C.
Town M.
Favier V.
Genoni L.,
Pouzenc C.
Pellegrini A. (2010). Extremely stable boundary layer on the Antarctic plateau.
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Trouvilliez A. (2010). Modélisation et quantification de, la neige soufflée en Antarctique, . Bachelor's thesis, , .
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Ricaud, P.
Derrien S
Chaboureau J. P.
Attié J. L.
Rose T.
Czecala H.
Genthon C.
Genoni L. (2010). First measurements of temperature and humidity in the PBL at Dome C, Antarctica.
Abstract: ISARS conference proceedings
Programme: 1013
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GENTHON C, MAGAND O, KRINNER G, FILY M, . (2009). Do climate models underestimate snow accumulation on the Antarctic plateau? A re-evaluation of/from in situ observations in East Wilkes and Victoria Lands
. Annals of glaciology, 50, 61–65.
Abstract: It has been suggested that meteorological and climate models underestimate snow accumulation on the Antarctic plateau, because accumulation (or surface mass balance (SMB)) is dominated by clear-sky precipitation while this process is not properly taken into account in the models. Here, we show that differences between model and field SMB data are much reduced when the in situ SMB reports used to evaluate the models are filtered through quality-control criteria and less reliable reports are subsequently left out. We thus argue that, although not necessarily unsupported, model biases and their interpretations in terms of clear-sky vs synoptic precipitation on the Antarctic plateau may have been overstated in the past. To avoid such misleading issues, it is important that in situ SMB reports of insufficient or unassessed reliability are discarded, even at the cost of a strong reduction in spatial sampling and coverage.
Keywords: Accumulation, algorithm performance, Antarctica, Antarctique, Antártico, atmospheric precipitation, Balance glaciar, Balance masa, Bilan glaciaire, Bilan masse, Ciel serein, Cielo sereno, Clear sky, Climate models, Dato observación, Diamond dust, Donnée observation, Glacier balance, ground truth, ice sheets, Inlandsis, Masa de hielo, mass balance, Modèle climat, Observation data, Performance algorithme, Polar region, polar regions, Polvo brillante, Poudrin de glace, Precipitación atmosférica, Précipitation atmosphérique, Realidad terreno, Réalité terrain, Région Polaire, Terre Victoria, Terre Wilkes, Tierra Victoria, Tierra Wilkes, Victoria Land, Wilkes Land, Zona polar, Zone polaire,
Programme: 1013
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Barandun M. (2009). Studies of Antarctic precipitation statistics.
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Genthon C, Krinner G, Castebrunet H, . (2009). Antarctic precipitation and climate-change predictions: horizontal resolution and margin vs plateau issues
. Annals of Glaciology, 50(50), 55–60.
Abstract: All climate models participating in the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, as made available by the Program for Climate Model Diagnosis and Intercomparison (PCMDI) as the Coupled Model Intercomparison Project 3 (CMIP3) archive, predict a significant surface warming of Antarctica by the end of the 21st century under a moderate (SRESA1B) greenhouse-gas scenario. All models but one predict a concurrent precipitation increase but with a large scatter of results. The models with finer horizontal resolution tend to predict a larger precipitation increase. Because modeled Antarctic surface mass balance is known to be sensitive to horizontal resolution, extrapolating predictions from the different models with respect to model resolution may provide simple yet better multi-model estimates of Antarctic precipitation change than mere averaging or even more complex approaches. Using such extrapolation, a conservative estimate of the predicted precipitation increase at the end of the 21st century is +30 kg m2a1 on the grounded ice sheet, corresponding to a >1 mm a1 sea-level rise. About three-quarters of this rise originates from the marginal regions of the Antarctic ice sheet with surface elevation below 2250 m. This is where field programs are most urgently needed to better understand and monitor accumulation at the surface of Antarctica, and to improve and verify prediction models.
Programme: 1013
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