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| Author | Gallée H, Barral H, Vignon E, Genthon C, | ||||
| Title | A case study of a low-level jet during OPALE | Type | Journal Article | ||
| Year | 2015 | Publication | Atmospheric Chemistry and Physics | Abbreviated Journal | |
| Volume | 15 | Issue | 11 | Pages | 6237-6246 |
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| Programme | 1013 | ||||
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| Publisher | Copernicus GmbH | Place of Publication | Editor | ||
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| Notes | Approved | yes | |||
| Call Number | Serial | 6250 | |||
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| Author | Gallée, H., S. Preunkert, S. Argentini, M. M. Frey, C. Genthon, B. Jourdain, I. Pietroni, G. Casasanta, H. Barral, E. Vignon, and M. Legrand | ||||
| Title | Characterization of the boundary layer at Dome C (East Antarctica) during the OPALE summer campaign | Type | Journal Article | ||
| Year | 2015 | Publication | Atmos. Chem. Phys. | Abbreviated Journal | |
| Volume | 15 | Issue | Pages | 6225-6236 | |
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| Abstract | Regional climate model MAR (Modèle Atmosphérique Régional) was run for the region of Dome C located on the East Antarctic plateau, during Antarctic summer 2011–2012, in order to refine our understanding of meteorological conditions during the OPALE tropospheric chemistry campaign. A very high vertical resolution is set up in the lower troposphere, with a grid spacing of roughly 2 m. Model output is compared with temperatures and winds observed near the surface and from a 45 m high tower as well as sodar and radiation data. MAR is generally in very good agreement with the observations, but sometimes underestimates cloud formation, leading to an underestimation of the simulated downward long-wave radiation. Absorbed short-wave radiation may also be slightly overestimated due to an underestimation of the snow albedo, and this influences the surface energy budget and atmospheric turbulence. Nevertheless, the model provides sufficiently reliable information about surface turbulent fluxes, vertical profiles of vertical diffusion coefficients and boundary layer height when discussing the representativeness of chemical measurements made nearby the ground surface during field campaigns conducted at Concordia station located at Dome C (3233 m above sea level). | ||||
| Programme | 1013 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7316 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 6311 | |||
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| Author | Slemr F, Angot H, Dommergue A, Magand O, Barret M, Weigelt A, Ebinghaus R, Brunke E-G, Pfaffhuber K A, Edwards G, Howard D, Powell J, Keywood M, Wang F, | ||||
| Title | Comparison of mercury concentrations measured at several sites in the Southern Hemisphere | Type | Journal Article | ||
| Year | 2015 | Publication | Atmos. Chem. Phys. | Abbreviated Journal | |
| Volume | 15 | Issue | 6 | Pages | 3125-3133 |
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| Abstract | Our knowledge of the distribution of mercury concentrations in air of the Southern Hemisphere was until recently based mostly on intermittent measurements made during ship cruises. In the last few years continuous mercury monitoring has commenced at several sites in the Southern Hemisphere, providing new and more refined information. In this paper we compare mercury measurements at several remote sites in the Southern Hemisphere made over a period of at least 1 year at each location. Averages of monthly medians show similar although small seasonal variations at both Cape Point and Amsterdam Island. A pronounced seasonal variation at Troll research station in Antarctica is due to frequent mercury depletion events in the austral spring. Due to large scatter and large standard deviations of monthly average median mercury concentrations at Cape Grim, no systematic seasonal variation could be found there. Nevertheless, the annual average mercury concentrations at all sites during the 2007–2013 period varied only between 0.85 and 1.05 ng m−3. Part of this variability is likely due to systematic measurement uncertainties which we propose can be further reduced by improved calibration procedures. We conclude that mercury is much more uniformly distributed throughout the Southern Hemisphere than the distributions suggested by measurements made onboard ships. This finding implies that smaller trends can be detected in shorter time periods. We also report a change in the trend sign at Cape Point from decreasing mercury concentrations in 1996–2004 to increasing concentrations since 2007. | ||||
| Programme | 1028 | ||||
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| Publisher | Copernicus Publications | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4942 | |||
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| Author | T. A. Berhanu, J. Savarino, J. Erbland, W. C. Vicars, S. Preunkert, J. F. Martins, M. S. Johnson | ||||
| Title | Isotopic effects of nitrate photochemistry in snow: a field study at Dome C, Antarctica | Type | Journal | ||
| Year | 2015 | Publication | Atmospheric Chemistry and Physics | Abbreviated Journal | |
| Volume | 15 | Issue | 19 | Pages | 11243-11256 |
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| Abstract | Abstract. Stable Isotope Ratios Of Nitrate Preserved In Deep Ice Cores Are Expected To Provide Unique And Valuable Information Regarding Paleoatmospheric Processes. However, Due To The Post-depositional Loss Of Nitrate In Snow, This Information May Be Erased Or Significantly Modified By Physical Or Photochemical Processes Before Preservation In Ice. We Investigated The Role Of Solar Uv Photolysis In The Post-depositional Modification Of Nitrate Mass And Stable Isotope Ratios At Dome C, Antarctica, During The Austral Summer Of 2011/2012. Two 30 Cm Snow Pits Were Filled With Homogenized Drifted Snow From The Vicinity Of The Base. One Of These Pits Was Covered With A Plexiglass Plate That Transmits Solar Uv Radiation, While The Other Was Covered With A Different Plexiglass Plate Having A Low Uv Transmittance. Samples Were Then Collected From Each Pit At A 2–5 Cm Depth Resolution And A 10-day Frequency. At The End Of The Season, A Comparable Nitrate Mass Loss Was Observed In Both Pits For The Top-level Samples (0–7 Cm) Attributed To Mixing With The Surrounding Snow. After Excluding Samples Impacted By The Mixing Process, We Derived An Average Apparent Nitrogen Isotopic Fractionation (15ϵapp) Of −67.8 ± 12 ‰ For The Snow Nitrate Exposed To Solar Uv Using The Nitrate Stable Isotope Ratios And Concentration Measurements. For The Control Samples In Which Solar Uv Was Blocked, An Apparent Average 15ϵapp Value Of −12.0 ± 1.7 ‰ Was Derived. This Difference Strongly Suggests That Solar Uv Photolysis Plays A Dominant Role In Driving The Isotopic Fractionation Of Nitrate In Snow. We Have Estimated A Purely Photolytic Nitrogen Isotopic Fractionation (15ϵphoto) Of −55.8 ± 12.0 ‰ From The Difference In The Derived Apparent Isotopic Fractionations Of The Two Experimental Fields, As Both Pits Were Exposed To Similar Physical Processes Except Exposure To Solar Uv. This Value Is In Close Agreement With The 15ϵphoto Value Of −47.9 ± 6.8 ‰ Derived In A Laboratory Experiment Simulated For Dome C Conditions (Berhanu Et Al., 2014). We Have Also Observed An Insensitivity Of 15ϵ With Depth In The Snowpack Under The Given Experimental Setup. This Is Due To The Uniform Attenuation Of Incoming Solar Uv By Snow, As 15ϵ Is Strongly Dependent On The Spectral Distribution Of The Incoming Light Flux. Together With Earlier Work, The Results Presented Here Represent A Strong Body Of Evidence That Solar Uv Photolysis Is The Most Relevant Post-depositional Process Modifying The Stable Isotope Ratios Of Snow Nitrate At Low-accumulation Sites, Where Many Deep Ice Cores Are Drilled. Nevertheless, Modeling The Loss Of Nitrate In Snow Is Still Required Before A Robust Interpretation Of Ice Core Records Can Be Provided. | ||||
| Programme | 1011 | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7316 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 8146 | |||
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| Author | Legrand M, Preunkert S, Frey M, Bartels-Rausch Th, Kukui A, King M D, Savarino J, Kerbrat M, Jourdain B, | ||||
| Title | Large mixing ratios of atmospheric nitrous acid (HONO) at Concordia (East Antarctic Plateau) in summer: a strong source from surface snow? | Type | Journal Article | ||
| Year | 2014 | Publication | Atmospheric Chemistry and Physics | Abbreviated Journal | 1680-7316 |
| Volume | 14 | Issue | 18 | Pages | 9963-9976 |
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| Abstract | During the austral summer 2011/2012 atmospheric nitrous acid (HONO) was investigated for the second
time at the Concordia site (75060 S, 123330 E), located on the East Antarctic Plateau, by deploying a long-path absorption photometer (LOPAP). Hourly mixing ratios of HONO measured in December 2011/January 2012 (35±5.0 pptv) were similar to those measured in December 2010/January 2011 (30.4±3.5 pptv). The large value of the HONO mixing ratio at the remote Concordia site suggests a local source of HONO in addition to weak production from oxidation of NO by the OH radical. Laboratory experiments demonstrate that surface snow removed from Concordia can produce gasphase HONO at mixing ratios half that of the NOx mixing ratio produced in the same experiment at typical temperatures encountered at Concordia in summer. Using these lab data and the emission flux of NOx from snow estimated from the vertical gradient of atmospheric concentrations measured during the campaign, a mean diurnal HONO snow emission ranging between 0.5 and 0.8×109 molecules cm-2 s-1 is calculated. Model calculations indicate that, in addition to around 1.2 pptv of HONO produced by the NO oxidation, these HONO snow emissions can only explain 6.5 to 10.5 pptv of HONO in the atmosphere at Concordia. To explain the difference between observed and simulated HONO mixing ratios, tests were done both in the field and at lab to explore the possibility that the presence of HNO4 had biased the measurements of HONO. |
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| Programme | 1011 | ||||
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| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Copernicus GmbH | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7316 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 5968 | |||
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| Author | Frey M M, Brough N, France J L, Anderson P S, Traulle O, King M D, Jones A E, Wolff E W, Savarino J, | ||||
| Title | The diurnal variability of atmospheric nitrogen oxides (NO and NO2) above the Antarctic Plateau driven by atmospheric stability and snow emissions | Type | Journal Article | ||
| Year | 2013 | Publication | ATMOSPHERIC CHEMISTRY AND PHYSICS | Abbreviated Journal | |
| Volume | 13 | Issue | 6 | Pages | 3045-3062 |
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| Abstract | Atmospheric nitrogen oxides (NO and NO2) were observed at Dome C, East Antarctica (75.1° S, 123.3° E, 3233 m), for a total of 50 days, from 10 December 2009 to 28 January 2010. Average (±1σ) mixing ratios at 1.0 m of NO and NO2, the latter measured for the first time on the East Antarctic Plateau, were 111 (±89) and 98 (±89) pptv, respectively. Atmospheric mixing ratios are on average comparable to those observed previously at South Pole, but in contrast show strong diurnal variability: a minimum around local noon and a maximum in the early evening coincide with the development and collapse of a convective boundary layer. The asymmetric diurnal cycle of NOx concentrations and likely any other chemical tracer with a photolytic surface source is driven by the turbulent diffusivity and height of the atmospheric boundary layer, with the former controlling the magnitude of the vertical flux and the latter the size of the volume into which snow emissions are transported. In particular, the average (±1σ) NOx emission flux from 22 December 2009 to 28 January 2010, estimated from atmospheric concentration gradients, was 8.2 (±7.4) × 1012 molecule m-2 s-1 belongs to the largest values measured so far in the polar regions and explains the 3-fold increase in mixing ratios in the early evening when the boundary layer becomes very shallow. Dome C is likely not representative for the entire East Antarctic Plateau but illustrates the need of an accurate description of the boundary layer above snow in atmospheric chemistry models. A simple nitrate photolysis model matches the observed median diurnal NOx flux during the day but has significant low bias during the night. The difference is significant taking into account the total random error in flux observations and model uncertainties due to the variability of NO3- concentrations in snow and potential contributions from NO2- photolysis. This highlights uncertainties in the parameterization of the photolytic NOx source in natural snowpacks, such as the poorly constrained quantum yield of nitrate photolysis. A steady-state analysis of the NO2 : NO ratios indicates that peroxy (HO2 + RO2) or other radical concentrations in the boundary layer of Dome C are either higher than measured elsewhere in the polar regions or other processes leading to enhanced NO2 have to be invoked. These results confirm the existence of a strongly oxidising canopy enveloping the East Antarctic Plateau in summer.
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| Programme | 1011 | ||||
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| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4468 | |||
| Permanent link to this record | |||||
| Author | J. Kuttippurath, F. Lefevre, J.-P. Pommereau, H. K. Roscoe, F. Goutail, A. Pazmino, and J. D. Shanklin | ||||
| Title | Antarctic ozone loss in 1979–2010: first sign of ozone recovery | Type | Journal Article | ||
| Year | 2013 | Publication | Atmos. Chem. Phys. | Abbreviated Journal | |
| Volume | 13 | Issue | 3 | Pages | 1625-1635 |
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| Abstract | A long-term ozone loss time series is necessary to understand the evolution of ozone in Antarctica. Therefore, we construct the time series using ground-based, satellite and bias-corrected multi-sensor reanalysis (MSR) data sets for the period 1989–2010. The trends in ozone over 1979–2010 are also estimated to further elucidate its evolution in the wake of decreasing halogen levels in the stratosphere. Our analysis with ground-based observations shows that the average ozone loss in the Antarctic is about −33 to −50% (−90 to −155 DU (Dobson Unit)) in 1989–1992, and then stayed at around −48% (−160 DU). The ozone loss in the warmer winters (e.g. 2002 and 2004) is lower (−37 to −46%), and in the very cold winters (e.g. 2003 and 2006) it is higher (−52 to −55%). These loss estimates are in good agreement with those estimated from satellite observations, where the differences are less than ±3%. The ozone trends based on the equivalent effective Antarctic stratospheric chlorine (EEASC) and piecewise linear trend (PWLT) functions for the vortex averaged ground-based, Total Ozone Mapping Spectrometer/Ozone Monitoring Instrument (TOMS/OMI), and MSR data averaged over September–November exhibit about −4.6 DU yr−1 over 1979–1999, corroborating the role of halogens in the ozone decrease during the period. The ozone trends computed for the 2000–2010 period are about +1 DU yr−1 for EEASC and +2.6 DU yr−1 for the PWLT functions. The larger positive PWLT trends for the 2000–2010 period indicate the influence of dynamics and other basis functions on the increase of ozone. The trends in both periods are significant at 95% confidence intervals for all analyses. Therefore, our study suggests that Antarctic ozone shows a significant positive trend toward its recovery, and hence, leaves a clear signature of the successful implementation of the Montreal Protocol. | ||||
| Programme | 209 | ||||
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| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4460 | |||
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| Author | Pison I, Ringeval B, Bousquet P, Prigent C, Papa F, | ||||
| Title | Stable atmospheric methane in the 2000s: key-role of emissions from natural wetlands | Type | Journal Article | ||
| Year | 2013 | Publication | Atmos. Chem. Phys. | Abbreviated Journal | |
| Volume | 13 | Issue | 23 | Pages | 11609-11623 |
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| Abstract | |||||
| Programme | 416 | ||||
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| Publisher | Copernicus Publications | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4780 | |||
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| Author | Klonecki A, Pommier M, Clerbaux C, Ancellet G, Cammas J-P, Coheur P-F, Cozic A, Diskin G S, Hadji-Lazaro J, Hauglustaine D A, Hurtmans D, Khattatov B, Lamarque J-F, Law K S, Nedelec P, Paris J-D, Podolske J R, Prunet P, Schlager H, Szopa S, Turquety S, | ||||
| Title | Assimilation of IASI satellite CO fields into a global chemistry transport model for validation against aircraft measurements | Type | Journal Article | ||
| Year | 2012 | Publication | ATMOSPHERIC CHEMISTRY AND PHYSICS | Abbreviated Journal | |
| Volume | 12 | Issue | 10 | Pages | 4493-4512 |
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| Abstract | This work evaluates the IASI CO product against independent in-situ aircraft data from the MOZAIC program and the POLARCAT aircraft campaign. The validation is carried out by analysing the impact of assimilation of eight months of IASI CO columns retrieved for the period of May to December 2008 into the global chemistry transport model LMDz-INCA. A modelling system based on a sub-optimal Kalman filter was developed and a specific treatment that takes into account the representativeness of observations at the scale of the model grid is applied to the IASI CO columns and associated errors before their assimilation in the model. Comparisons of the assimilated CO profiles with in situ CO measurements indicate that the assimilation leads to a considerable improvement of the model simulations in the middle troposphere as compared with a control run with no assimilation. Model biases in the simulation of background values are reduced and improvement in the simulation of very high concentrations is observed. The improvement is due to the transport by the model of the information present in the IASI CO retrievals. Our analysis also shows the impact of assimilation of CO on the representation of transport into the Arctic region during the POLARCAT summer campaign. A considerable increase in CO mixing ratios over the Asian source region was observed when assimilation was used leading to much higher values of CO during the cross-pole transport episode. These higher values are in good agreement with data from the POLARCAT flights that sampled this plume. | ||||
| Programme | 416 | ||||
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| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4268 | |||
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| Author | Gazeaux J, Bekki S, Naveau P, Keckhut P, Jumelet J, Parades J, David C, | ||||
| Title | Detection of particle layers in backscatter profiles: application to Antarctic lidar measurements | Type | Journal Article | ||
| Year | 2012 | Publication | Atmos. Chem. Phys. | Abbreviated Journal | 1680-7316 |
| Volume | 12 | Issue | 7 | Pages | 3205-3217 |
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| Programme | 209 | ||||
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| Publisher | Copernicus Publications | Place of Publication | Editor | ||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1680-7324 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | yes | |||
| Call Number | Serial | 4674 | |||
| Permanent link to this record | |||||