|
Gorodetskaya I V, Van Lipzig N P M, Van den Broeke M R, Mangold A, Boot W, Reijmer C H, . (2013). Meteorological regimes and accumulation patterns at Utsteinen, Dronning Maud Land, East Antarctica: Analysis of two contrasting years
. J. Geophys. Res., 118(4), 1700–1715.
Keywords: 3270 Time series analysis, 3307 Boundary layer processes, 3349 Polar meteorology, 3354 Precipitation, 3359 Radiative processes, Antarctica, AWS, katabatic, meteorological regimes, snow accumulation, synoptic,
Programme: 411
|
|
|
. (2013). The atmospheric HCHO budget at Dumont d'Urville (East Antarctica): Contribution of photochemical gas-phase production versus snow emissions
. J. Geophys. Res., 118(23), 13,319–13,337.
Abstract: HCHO was monitored throughout the year 2009 at the coastal East Antarctic site of Dumont d'Urville (DDU) using Aerolaser AL-4021 analyzers. The accurate determination of less than 100 pptv required optimization of the analyzers, in particular, to minimize effects of changing ambient temperatures. The impact of station activities and of the presence of large penguin colonies at the site in summer was scrutinized. The obtained contamination-free record indicates monthly means close to 50 pptv from May to September and a maximum of 200 pptv in January. Zero-dimensional and 2-D calculations suggest that in summer, the largest HCHO source is the gas-phase photochemistry (80%) mainly driven by methane oxidation, which is considerably greater than from snow emissions (20%). The influence of light alkenes, dimethyl sulfide, and halogens remains weak. In winter, snow emissions represent the main HCHO source (70%). These findings are compared to previous studies conducted at the West Antarctic coast. It is shown that in summer the HCHO production from methane chemistry is 3 times more efficient at DDU than at the west coast due to more frequent arrival of oxidant-rich air masses from inland Antarctica. Halogen chemistry is found to represent a weak HCHO sink at both West and East Antarctica. Compared to DDU, the shallower atmospheric boundary layer and the less efficient gas-phase production at the west coast make the snow pack the dominant HCHO source (85%) compared to gas-phase photochemistry (15%) there in summer.
Keywords: atmospheric HCHO, coastal Antarctica, oxidative capacity, 0365 Troposphere: composition and chemistry, 0322 Constituent sources and sinks,
Programme: 414
|
|
|
. (2013). Reassessing the variability in atmospheric H2 using the two-way nested TM5 model
. J. Geophys. Res., 118(9), 3764–3780.
Keywords: Hydrogen isotopes, Molecular hydrogen, Chemical Transport Model, Tropospheric budget, Dry deposition, Sources and sinks, 0368 Troposphere: constituent transport and chemistry, 0365 Troposphere: composition and chemistry, 0322 Constituent sources and sinks, 0315 Biosphere/atmosphere interactions, 0317 Chemical kinetic and photochemical properties,
Programme: 416
|
|
|
Koukouli M E, Lerot C, Granville J, Goutail F, Lambert J-C, Pommereau J-P, Balis D, Zyrichidou I, Van Roozendael M, Coldewey-Egbers M, Loyola D, Labow G, Frith S, Spurr R, Zehner C, . (2015). Evaluating a new homogeneous total ozone climate data record from GOME/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A. Journal of Geophysical Research: Atmospheres, 120(23), 2015JD023699.
Abstract: The European Space Agency's Ozone Climate Change Initiative (O3-CCI) project aims at producing and validating a number of high-quality ozone data products generated from different satellite sensors. For total ozone, the O3-CCI approach consists of minimizing sources of bias and systematic uncertainties by applying a common retrieval algorithm to all level 1 data sets, in order to enhance the consistency between the level 2 data sets from individual sensors. Here we present the evaluation of the total ozone products from the European sensors Global Ozone Monitoring Experiment (GOME)/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A produced with the GOME-type Direct FITting (GODFIT) algorithm v3. Measurements from the three sensors span more than 16 years, from 1996 to 2012. In this work, we present the latest O3-CCI total ozone validation results using as reference ground-based measurements from Brewer and Dobson spectrophotometers archived at the World Ozone and UV Data Centre of the World Meteorological Organization as well as from UV-visible differential optical absorption spectroscopy (DOAS)/Système D′Analyse par Observations Zénithales (SAOZ) instruments from the Network for the Detection of Atmospheric Composition Change. In particular, we investigate possible dependencies in these new GODFIT v3 total ozone data sets with respect to latitude, season, solar zenith angle, and different cloud parameters, using the most adequate type of ground-based instrument. We show that these three O3-CCI total ozone data products behave very similarly and are less sensitive to instrumental degradation, mainly as a result of the new reflectance soft-calibration scheme. The mean bias to the ground-based observations is found to be within the 1 ± 1% level for all three sensors while the near-zero decadal stability of the total ozone columns (TOCs) provided by the three European instruments falls well within the 1–3% requirement of the European Space Agency's Ozone Climate Change Initiative project.
Keywords: 0340 Middle atmosphere: composition and chemistry, 0394 Instruments and techniques, 0480 Remote sensing, Brewer, Dobson, GOME-2, SCIAMACHY, total ozone, validation,
Programme: 209
|
|
|
Koukouli M E, Lerot C, Granville J, Goutail F, Lambert J-C, Pommereau J-P, Balis D, Zyrichidou I, Van Roozendael M, Coldewey-Egbers M, Loyola D, Labow G, Frith S, Spurr R, Zehner C, . (2015). Evaluating a new homogeneous total ozone climate data record from GOME/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A. Journal of Geophysical Research: Atmospheres, 120(23), 12,296–12,312.
Abstract: The European Space Agency's Ozone Climate Change Initiative (O3-CCI) project aims at producing and validating a number of high-quality ozone data products generated from different satellite sensors. For total ozone, the O3-CCI approach consists of minimizing sources of bias and systematic uncertainties by applying a common retrieval algorithm to all level 1 data sets, in order to enhance the consistency between the level 2 data sets from individual sensors. Here we present the evaluation of the total ozone products from the European sensors Global Ozone Monitoring Experiment (GOME)/ERS-2, SCIAMACHY/Envisat, and GOME-2/MetOp-A produced with the GOME-type Direct FITting (GODFIT) algorithm v3. Measurements from the three sensors span more than 16 years, from 1996 to 2012. In this work, we present the latest O3-CCI total ozone validation results using as reference ground-based measurements from Brewer and Dobson spectrophotometers archived at the World Ozone and UV Data Centre of the World Meteorological Organization as well as from UV-visible differential optical absorption spectroscopy (DOAS)/Système D′Analyse par Observations Zénithales (SAOZ) instruments from the Network for the Detection of Atmospheric Composition Change. In particular, we investigate possible dependencies in these new GODFIT v3 total ozone data sets with respect to latitude, season, solar zenith angle, and different cloud parameters, using the most adequate type of ground-based instrument. We show that these three O3-CCI total ozone data products behave very similarly and are less sensitive to instrumental degradation, mainly as a result of the new reflectance soft-calibration scheme. The mean bias to the ground-based observations is found to be within the 1 ± 1% level for all three sensors while the near-zero decadal stability of the total ozone columns (TOCs) provided by the three European instruments falls well within the 1–3% requirement of the European Space Agency's Ozone Climate Change Initiative project.
Keywords: total ozone, SCIAMACHY, Brewer, Dobson, GOME-2, validation, 0340 Middle atmosphere: composition and chemistry, 0394 Instruments and techniques, 0480 Remote sensing,
Programme: 209
|
|
|
Steen-Larsen, H.C., Risi, C., Masson-Delmotte, V., Werner, M., Yoshimura, K. (2016). Evaluating the skills of isotope-enabled general circulation models against in situ atmospheric water vapor isotope observations. J. Geophys. Res., 122(1), 2016JD025443.
Abstract: The skills of isotope-enabled general circulation models are evaluated against atmospheric water vapor isotopes. We have combined in situ observations of surface water vapor isotopes spanning multiple field seasons (2010, 2011, and 2012) from the top of the Greenland Ice Sheet (NEEM site: 77.45°N, 51.05°W, 2484 m above sea level) with observations from the marine boundary layer of the North Atlantic and Arctic Ocean (Bermuda Islands 32.26°N, 64.88°W, year: 2012; south coast of Iceland 63.83°N, 21.47°W, year: 2012; South Greenland 61.21°N, 47.17°W, year: 2012; Svalbard 78.92°N, 11.92°E, year: 2014). This allows us to benchmark the ability to simulate the daily water vapor isotope variations from five different simulations using isotope-enabled general circulation models. Our model-data comparison documents clear isotope biases both on top of the Greenland Ice Sheet (1–11‰ for δ18O and 4–19‰ for d-excess depending on model and season) and in the marine boundary layer (maximum differences for the following: Bermuda δ18O = ~1‰, d-excess = ~3‰; South coast of Iceland δ18O = ~2‰, d-excess = ~ 5‰; South Greenland δ18O = ~4‰, d-excess = ~7‰; Svalbard δ18O = ~2‰, d-excess = ~7‰). We find that the simulated isotope biases are not just explained by simulated biases in temperature and humidity. Instead, we argue that these isotope biases are related to a poor simulation of the spatial structure of the marine boundary layer water vapor isotopic composition. Furthermore, we specifically show that the marine boundary layer water vapor isotopes of the Baffin Bay region show strong influence on the water vapor isotopes at the NEEM deep ice core-drilling site in northwest Greenland. Our evaluation of the simulations using isotope-enabled general circulation models also documents wide intermodel spatial variability in the Arctic. This stresses the importance of a coordinated water vapor isotope-monitoring network in order to discriminate amongst these model behaviors.
Programme: 1134
|
|
|
. (2017). Antarctic boundary layer parametrization in a general circulation model: 1-D simulations facing summer observations at Dome C (Vol. 122).
Keywords: Antarctic Plateau atmospheric boundary layer GABLS4 general circulation model physical parametrizations
Programme: 1013
|
|
|
Christophe Genthon, Richard Forbes, Etienne Vignon, Andrew Gettelman, Jean-Baptiste Madeleine. (2018). (Vol. 123).
Abstract: Key Points Ruosteenoja et al.'s () claim that supersaturation in the surface atmosphere is unrealistic and necessarily spurious and incorrect Supersaturations are a reality that an increasing number of atmospheric models can reproduce even in the surface atmosphere Modelers should not artificially cap relative humidity at 100% when feeding climate model archives
Programme: 1013
|
|
|
F. Carbone, A. G. Bruno, A. Naccarato, F. De Simone, C. N. Gencarelli, F. Sprovieri, I. M. Hedgecock, M. S. Landis, H. Skov, K. A. Pfaffhuber, K. A. Read, L. Martin, H. Angot, A. Dommergue, O. Magand, N. Pirrone. (2018). The Superstatistical Nature and Interoccurrence Time of Atmospheric Mercury Concentration Fluctuations (Vol. 123).
Abstract: The probability density function (PDF) of the time intervals between subsequent extreme events in atmospheric Hg0 concentration data series from different latitudes has been investigated. The Hg0 dynamic possesses a long-term memory autocorrelation function. Above a fixed threshold Q in the data, the PDFs of the interoccurrence time of the Hg0 data are well described by a Tsallis q-exponential function. This PDF behavior has been explained in the framework of superstatistics, where the competition between multiple mesoscopic processes affects the macroscopic dynamics. An extensive parameter ?, encompassing all possible fluctuations related to mesoscopic phenomena, has been identified. It follows a ?2 distribution, indicative of the superstatistical nature of the overall process. Shuffling the data series destroys the long-term memory, the distributions become independent of Q, and the PDFs collapse on to the same exponential distribution. The possible central role of atmospheric turbulence on extreme events in the Hg0 data is highlighted.
Keywords: atmospheric turbulence interoccurrence times mercury superstatistics universal scaling
Programme: 1028
|
|
|
Elsa Gautier, Joel Savarino, Joseph Erbland, James Farquhar. (2018). SO2 Oxidation Kinetics Leave a Consistent Isotopic Imprint on Volcanic Ice Core Sulfate (Vol. 123).
Abstract: This work presents measurements of time-resolved mass-independently fractionated sulfate of volcanic origin from Antarctic ice core records that cover the last 2,600 years. These measurements are used to evaluate the time dependence of the deposited isotopic signal and to extract the isotopic characteristics of the reactions yielding sulfate from stratospheric volcanic eruptions in the modern atmosphere. Time evolution of the signal in snow (years) with respect to the fast SO2 oxidation in the stratosphere suggests that photochemically produced condensed phase is rapidly and continuously separated from the gas phase and preserved during transportation and deposition on the polar ice cap. On some eruptions, a nonzero isotopic mass balance highlights that a part of the signal can be lost during transport and/or deposition. The large number of volcanic events studied allows the ?33S versus ?36S and ?34S versus ?33S slopes to be constrained at ?1.56 (1? = 0.25) and 0.09 (1? = 0.02), respectively. The ?33S versus ?36S slope refines a prior determinations of ?36S/?33S = ?4 and overlaps the range observed for sulfur seen in early Earth samples (Archean). In recent volcanogenic sulfate, the ?33S versus ?34S differs, however, from the Archean record. The similitude for ?36S/?33S and the difference for ?33S/?34S suggest similar mass-independently fractionated sulfate processes to the Archean atmosphere. Using a simple model, we highlight that a combination of several mechanisms is needed to reproduce the observed isotopic trends and suggest a greater contribution from mass-dependent oxidation by OH in the modern atmosphere.
Keywords: Antarctica ice core sulfur mass-independent isotope fractionation volcanic eruption
Programme: 1177
|
|