Publications of Charles Amory
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See detailAntarctica-Regional Climate and Surface Mass Budget
Favier, Vincent; Krinner, Gerhard; Amory, Charles ULiege et al

in Current Climate Change Reports (2017)

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See detailReconstructions of the 1900–2015 Greenland ice sheet surface mass balance using the regional climate MAR model
Fettweis, Xavier ULiege; Box, Jason; Agosta, Cécile ULiege et al

in Cryosphere (2017), 11

With the aim of studying the recent Greenland ice sheet (GrIS) surface mass balance (SMB) decrease relative to the last century, we have forced the regional climate MAR (Modèle Atmosphérique Régional ... [more ▼]

With the aim of studying the recent Greenland ice sheet (GrIS) surface mass balance (SMB) decrease relative to the last century, we have forced the regional climate MAR (Modèle Atmosphérique Régional; version 3.5.2) model with the ERA-Interim (ECMWF Interim Re-Analysis; 1979–2015), ERA-40 (1958–2001), NCEP–NCARv1 (National Centers for Environmental Prediction–National Center for Atmospheric Research Reanalysis version 1; 1948–2015), NCEP–NCARv2 (1979–2015), JRA-55 (Japanese 55-year Reanalysis; 1958–2014), 20CRv2(c) (Twentieth Century Reanalysis version 2; 1900–2014) and ERA-20C (1900–2010) reanalyses. While all these forcing products are reanalyses that are assumed to represent the same climate, they produce significant differences in the MAR-simulated SMB over their common period. A temperature adjustment of +1 °C (respectively −1 °C) was, for example, needed at the MAR boundaries with ERA-20C (20CRv2) reanalysis, given that ERA-20C (20CRv2) is ∼ 1 °C colder (warmer) than ERA-Interim over Greenland during the period 1980–2010. Comparisons with daily PROMICE (Programme for Monitoring of the Greenland Ice Sheet) near-surface observations support these adjustments. Comparisons with SMB measurements, ice cores and satellite-derived melt extent reveal the most accurate forcing datasets for the simulation of the GrIS SMB to be ERA-Interim and NCEP–NCARv1. However, some biases remain in MAR, suggesting that some improvements are still needed in its cloudiness and radiative schemes as well as in the representation of the bare ice albedo. Results from all MAR simulations indicate that (i) the period 1961–1990, commonly chosen as a stable reference period for Greenland SMB and ice dynamics, is actually a period of anomalously positive SMB (∼ +40 Gt yr−1) compared to 1900–2010; (ii) SMB has decreased significantly after this reference period due to increasing and unprecedented melt reaching the highest rates in the 120-year common period; (iii) before 1960, both ERA-20C and 20CRv2-forced MAR simulations suggest a significant precipitation increase over 1900–1950, but this increase could be the result of an artefact in the reanalyses that are not well-enough constrained by observations during this period and (iv) since the 1980s, snowfall is quite stable after having reached a maximum in the 1970s. These MAR-based SMB and accumulation reconstructions are, however, quite similar to those from Box (2013) after 1930 and confirm that SMB was quite stable from the 1940s to the 1990s. Finally, only the ERA-20C-forced simulation suggests that SMB during the 1920–1930 warm period over Greenland was comparable to the SMB of the 2000s, due to both higher melt and lower precipitation than normal. [less ▲]

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See detailSeasonal variations in drag coefficient over a sastrugi-covered snowfield in coastal East Antarctica
Amory, Charles ULiege; Gallee, Hubert; Naaim-Bouvet, Florence et al

in Boundary-Layer Meteorology (2017)

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See detailMomentum- and Heat-Flux Parameterization at Dome C, Antarctica: A Sensitivity Study
Vignon, Etienne; Genthon, Christophe; Barral, Hélène et al

in Boundary-Layer Meteorology (2016)

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See detailBrief communication: Two well-marked cases of aerodynamic adjustment of sastrugi
Amory, Charles ULiege; Naaim-Bouvet, Florence; Gallée, Hubert et al

in Cryosphere (2016)

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See detailComparison between observed and simulated aeolian snow mass fluxes in Adélie Land, East Antarctica
Amory, Charles ULiege; Trouvillez, A.; Gallée, H. et al

in Cryosphere (2015), 9

The regional climate model MAR including a coupled snow pack/aeolian snow transport parameterisation is compared with aeolian snow mass fluxes at a fine spatial resolution (5 km horizontally and 2 m ... [more ▼]

The regional climate model MAR including a coupled snow pack/aeolian snow transport parameterisation is compared with aeolian snow mass fluxes at a fine spatial resolution (5 km horizontally and 2 m vertically) and at a fine temporal resolution (30 min) over 1 month in Antarctica. Numerous feedbacks are taken into account in the MAR including the drag partitioning caused by the roughness elements. Wind speed is correctly simulated with a positive value of the Nash test (0.60 and 0.37) but the wind speeds above 10 m s−1 are underestimated. The aeolian snow transport events are correctly reproduced with a good temporal resolution except for the aeolian snow transport events with a particles' maximum height below 1 m. The simulated threshold friction velocity, calculated without snowfall, is overestimated. The simulated aeolian snow mass fluxes between 0 to 2 m have the same variations but are underestimated compared to the second-generation FlowCapt values and so is the simulated relative humidity at 2 m. This underestimation is not entirely due to the underestimation of the simulated wind speed. The MAR underestimates the aeolian snow quantity that pass through the first two meters by a factor ten compared to the second-generation FlowCapt value (13 990 kg m−1 and 151 509 kg m−1 respectively). It will conduct the MAR, with this parametrisation, to underestimate the effect of the aeolian snow transport on the Antarctic surface mass balance. [less ▲]

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See detailCharacterization of the boundary layer at Dome C (East Antarctica) during the OPALE simmer campaign
Gallée, Hubert; Preunkert, Susanne; Argentini, Stefania et al

in Atmospheric Chemistry and Physics (2015)

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See detailA novel experimental study of aeolian snow transport in Adelie Land (Antarctica)
Trouvilliez, Alexandre; Naaim-Bouvet, Florence; Genthon, Christophe et al

in Cold Regions Science and Technology (2014), 108

None of the previous aeolian snow transport campaigns in Antarctica meet the requirements in terms of tempo- ral resolution, long-term series and qualified instruments for evaluations of meteorological ... [more ▼]

None of the previous aeolian snow transport campaigns in Antarctica meet the requirements in terms of tempo- ral resolution, long-term series and qualified instruments for evaluations of meteorological and climate models including parameterization for aeolian snow transport. Consequently, determining the quantity of snow transported remains a challenge. A field campaign was therefore launched in January 2009, in Adélie Land, Antarctica, to acquire new model-evaluation-oriented observations within the European ICE2SEA project, with the logistical support of the French polar Institute (IPEV). The available aeolian snow transport sensors are reviewed and the sensor that best suited our specific needs was chosen: FlowCaptTM acoustic sensors. Three au- tomatic weather stations were deployed with FlowCaptsTM close to the coast. The stations' locations are distinct, ranging from 1 to 100 km inland, one of them with a 7-m mast with six levels of anemometers and thermohygrometers. The fluid and impact threshold friction velocities recorded were 0.48 ± 0.09 m s− 1 and 0.4 ± 0.09 m s−1, respectively, with a high standard deviation of 0.12 ± 0.03 m s−1 and 0.13 ± 0.03 m s−1, respectively. The aeolian snow transport frequency in Adélie Land was very high with seasonal variation of trans- port occurring with minima during the austral summer. Seven percent of the aeolian snow transport events were drifting snow (maximum particle's height, b1 m above the surface). The snow quantity transported was above 1 kiloton per year in the first meter above the surface. [less ▲]

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See detailBlowing snow in coastal Adélie Land, Antarctica: three atmospheric-moisture issues
Barral, Hélène; Genthon, Christophe; Trouvilliez, Alexandre et al

in Cryosphere (2014)

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See detailSensitivity Study of the antarctic surface mass balance to snow erosion by the wind.
Gallée, Hubert; Agosta, Cécile ULiege; Amory, Charles ULiege et al

Conference (2014, August 26)

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