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23 results on '"Department of Geography [Sheffield]"'

1. Response to the discussion by Van Vliet-Lanoë et al. of the paper ‘Features caused by ground ice growth and decay in Late Pleistocene fluvial deposits, Paris Basin, France’ (Bertran et al., 2018, Geomorphology 310, 84–101)

Author: Kevin Manchuel, Pascal Bertran, Mark D. Bateman, Marianne Font, Eric Andrieux, Deborah Sicilia, Institut national de recherches archéologiques préventives (Inrap), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Centre National de la Recherche Scientifique (CNRS)-Université de Bordeaux (UB), University of Sheffield [Sheffield], Department of Geography [Sheffield], Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Normandie Université (NU), and EDF (EDF)
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Pleistocene, Faulting, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Fluvial, Context (language use), Last Glacial permafrost, 010502 geochemistry & geophysics, Permafrost, 01 natural sciences, Thermokarst, Sedimentary depositional environment, Paleontology, Terrace (geology), Paris Basin, Thermokarst lakes, Alluvium, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: (IF 3.82; Q1); International audience; The response by Van Vliet-Lanoë et al. to our paper on potential thermokarst features in Pleistocene alluvial deposits from the Paris Basin (France) presents inconsistencies that we consider here successively. These are (1) the map of the maximum extent of Pleistocene permafrost in France, (2) the genesis of liquefaction and fluidization structures in periglacial environments, (3) the origin of thermokarst lakes and recumbent folds, (4) the depositional context of sandy units, and (5) the age of the studied deposits. All structures result from the interplay between (1) the growth and degradation of ice wedges, which are responsible for the development of a mound-like topography (badland thermokarst reliefs) on the edge of the alluvial terrace and from the initiation of ponding elsewhere on the terrace, (2) the degradation of lithalsa that developed later in the lacustrine deposits. The sequence was dated confidently to the Late Weichselian.
Published: 2019
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2. Sinuous ridges in Chukhung crater, Tempe Terra, Mars: Implications for fluvial, glacial, and glaciofluvial activity

Author: Colman Gallagher, Stephen R. Lewis, Frances E. G. Butcher, Susan J. Conway, Robert D. Storrar, Matthew R. Balme, Neil Arnold, Joel Davis, Axel Hagermann, Department of Geography [Sheffield], University of Sheffield [Sheffield], The Open University [Milton Keynes] (OU), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University College Dublin [Dublin] (UCD), Scott Polar Research Institute, University of Cambridge [UK] (CAM), Sheffield Hallam University, University of Stirling, The Natural History Museum [London] (NHM), Arnold, Neil [0000-0001-7538-3999], and Apollo - University of Cambridge Repository
Subjects: 010504 meteorology & atmospheric sciences, Amazonian, Inverted paleochannels, glaciation, Fluvial, Mars, 01 natural sciences, Paleontology, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Impact crater, 0103 physical sciences, Glacial period, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Landform, fluvial, Astronomy and Astrophysics, 15. Life on land, Eskers, Space and Planetary Science, Ridge, Subaerial, Hesperian, Geology, Sinuous ridges
Abstract: International audience; We present a geomorphic map of Chukhung crater (38.47°N, 72.42°W) in central Tempe Terra, Mars. Chukhung crater formed ~3.6–2.1 Ga, between the early Hesperian and early Amazonian periods of Mars' geologic history. It hosts dendritic networks of crater wall valleys, broad crater floor valleys, mid-to-late-Amazonian-aged debris-covered glaciers, moraine-like deposits, and a radial assemblage of sinuous ridge landforms. We explore the origins of landforms in Chukhung crater, focusing in particular upon the sinuous ridges. In northern Chukhung crater, sinuous ridges extend downslope from fluvial valley systems on the northern crater wall. We interpret the northern sinuous ridges as inverted paleochannels: ridges formed by exhumation of resistant and/or indurated fluvial channel fill deposits. The origins of sinuous ridges on the southern floor of Chukhung crater are more ambiguous. They emerge from beneath moraine-like ridges which bound extant debris-covered glaciers extending from the southern wall of the crater. The southern sinuous ridges have numerous morphological and contextual similarities to eskers: ridges of glaciofluvial sediment deposited in meltwater conduits within or beneath wet-based glaciers. The close proximity of the northern and southern sinuous ridges, however, calls into question an interpretation which ascribes a different origin to each set. The similarity in the overarching process between esker and inverted channel formation (i.e., exposure by the removal of a bounding medium, be that ice or sediments/rock) results in convergence of form between eskers and inverted paleochannels. We discuss the esker-like characteristics of the southern sinuous ridges in detail, and argue that one of two ridge populations in southern Chukhung crater is best explained by the esker hypothesis while the other could be explained under either the esker or the inverted paleochannel hypothesis. Regardless of the specific formation mechanism for the southern sinuous ridges, we find that Chukhung crater has undergone significant modification by liquid water since its formation. The northern sinuous ridges and associated crater-wall valleys provide evidence for subaerial drainage of precipitation and/or snowmelt. This suggests that Chukhung crater, and possibly the surrounding region, experienced unusually warm and wet episodes between the early Hesperian and mid Amazonian. If some or all of the southern sinuous ridges are eskers, they could provide evidence for an additional influence of glacial meltwater in Chukhung crater during the mid-to-late Amazonian. If wet-based glaciation did occur in Chukhung crater, the location of the crater between major branches of the Tempe Fossae tectonic rift system would add to the growing body of evidence that elevated geothermal heat flux was an important driver of localized occurrences of recent wet-based glaciation on Mars.
Published: 2021
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3. Mass balance of the ice sheets and glaciers – Progress since AR5 and challenges

Author: Edward Hanna, Ben Smith, Francisco Navarro, Heiko Goelzer, Pippa L. Whitehouse, Frank Pattyn, Vincent Favier, Catherine Ritz, Miren Vizcaino, Michiel R. van den Broeke, Kevin Bulthuis, Department of Geography [Sheffield], University of Sheffield [Sheffield], Laboratoire de Glaciologie [Bruxelles], Université libre de Bruxelles (ULB), Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Utrecht University [Utrecht], Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Université de Liège, Sub Dynamics Meteorology, and Marine and Atmospheric Research
Subjects: geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Global warming, Earth and Planetary Sciences(all), Climate change, Glacier, 010502 geochemistry & geophysics, Climate change assessment, 01 natural sciences, Sciences de la terre et du cosmos, Ice dynamics, Glacier mass balance, Balance (accounting), 13. Climate action, Climatology, Taverne, General Earth and Planetary Sciences, Environmental science, F890 Geographical and Environmental Sciences not elsewhere classified, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, Ice sheet, Sciences exactes et naturelles, 0105 earth and related environmental sciences
Abstract: Recent research shows increasing decadal ice mass losses from the Greenland and Antarctic Ice Sheets and more generally from glaciers worldwide in the light of continued global warming. Here, in an update of our previous ISMASS paper (Hanna et al. 2013), we review recent observational estimates of ice sheet and glacier mass balance, and their related uncertainties, first briefly considering relevant monitoring methods. Focusing on the response to climate change during 1992–2018, and especially the post-IPCC AR5 period, we discuss recent changes in the relative contributions of ice sheets and glaciers to sea-level change. We assess recent advances in understanding of the relative importance of surface mass balance and ice dynamics in overall ice-sheet mass change. We also consider recent improvements in ice-sheet modelling, highlighting data-model linkages and the use of updated observational datasets in ice-sheet models. Finally, by identifying key deficiencies in the observations and models that hamper current understanding and limit reliability of future ice-sheet projections, we make recommendations to the research community for reducing these knowledge gaps. Our synthesis aims to provide a critical and timely review of the current state of the science in advance of the next Intergovernmental Panel on Climate Change Assessment Report that is due in 2021., SCOPUS: re.j, info:eu-repo/semantics/published
Published: 2020
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4. Morphometry of a glacier-linked esker in NW Tempe Terra, Mars, and implications for sediment-discharge dynamics of subglacial drainage

Author: Stephen R. Lewis, Susan J. Conway, Axel Hagermann, Matthew R. Balme, Robert D. Storrar, Frances E. G. Butcher, Colman Gallagher, Neil Arnold, School of Physical Sciences [Milton Keynes], Faculty of Science, Technology, Engineering and Mathematics [Milton Keynes], The Open University [Milton Keynes] (OU)-The Open University [Milton Keynes] (OU), Department of Geography [Sheffield], University of Sheffield [Sheffield], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University College Dublin [Dublin] (UCD), Scott Polar Research Institute, University of Cambridge [UK] (CAM), Sheffield Hallam University, University of Stirling, Butcher, Frances EG [0000-0002-5392-7286], Balme, Matthew R [0000-0001-5871-7475], Conway, Susan J [0000-0002-0577-2312], Storrar, Robert D [0000-0003-4738-0082], and Apollo - University of Cambridge Repository
Subjects: 010504 meteorology & atmospheric sciences, glaciers on Mars, 3705 Geology, 010502 geochemistry & geophysics, 01 natural sciences, Deposition (geology), [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Digital elevation model, Meltwater, Geomorphology, wet-based glaciation, 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Feature (archaeology), Sediment, Glacier, 37 Earth Sciences, Mars Exploration Program, 15. Life on land, 3709 Physical Geography and Environmental Geoscience, Mars geomorphology, Geophysics, esker, Space and Planetary Science, Ridge, glacial hydrology, 51 Physical Sciences, Geology
Abstract: International audience; We present a systematic, metre-scale characterisation of the 3D morphometry of an esker on Mars, and the first attempt to reconstruct the multi-stage dynamics of esker formation on Mars. Eskers are sinuous ridges comprising sediment deposited by meltwater draining through ice-confined tunnels within or beneath glaciers. Detailed morphometric insights into eskers on Mars are important for (i) informing morphometric tests of whether sinuous ridges elsewhere on Mars are eskers, and (ii) informing modelling experiments which aim to reconstruct the glaciological and environmental controls on esker formation on Mars. We use a digital elevation model generated from High Resolution Imaging Science Experiment (HiRISE) images to characterise the height and width of an extremely rare esker associated with a late-Amazonian-aged viscous flow feature (debris-covered glacier) in NW Tempe Terra, Mars. Our measurements suggest that the NW Tempe Terra esker is a 'stacked' formation comprising an underlying 'lower member' ridge that is superposed by a narrower 'upper member' ridge. We used a novel morphometric approach to test whether the apparent stacking records two distinct esker deposition regimes (either within the same drainage episode, or within temporally-separated drainage episodes). This approach posits that esker crest morphology is controlled by primary esker formation processes and, by extension, that portions of eskers with similar crest morphologies should have similar morphometric relationships. We predicted the morphometric relationships described by the constituent upper and lower member ridges based on 'reference relationships' observed for morphologically-similar portions of the esker where no evidence of stacking was observed. Our observations corresponded well with the predicted relationships, supporting our stacked esker hypothesis. We propose conceptual models, which invoke spatial and temporal variations in sediment supply and meltwater discharge, to explain the stacked morphology. These models are informed by morpho-sedimentary relationships observed along eskers on Earth.
Published: 2020
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5. The advance and retreat of the Irish Sea Ice Stream in the Celtic Sea and its influence on shelf evolution

Author: Lockhart, Edward, Scourse, James, Praeg, D, van Landeghem, Katrien J.J., Mellett, Claire, Saher, Margot, Callard, Louise, Chiverrell, Richard C., Benetti, Sara, Cofaigh, Colm Ó, Clark, Chris, School of Ocean Sciences [Menai Bridge], Bangor University, University of Exeter, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Wessex Archaeology [Salisbury], Department of Geography (UNIVERSITé DE DURHAM), Durham University, University of Liverpool, School of Geography and Environmental Sciences, University of Ulster, Department of Geography [Sheffield], University of Sheffield [Sheffield], European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016), School of Ocean Sciences [Bangor], Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Daniel, Praeg, and Multi-disciplinary Comparison of Fluid Venting from Gas Hydrate Systems on the Mediterranean and Brazilian Continental Margins over Glacial-Interglacial Timescales - SEAGAS - - H20202016-04-30 - 2019-04-29 - 656821 - VALID
Subjects: [SDU.STU.GM] Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SDU.STU] Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.ST] Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.STU.OC] Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, [SDU.STU.GL] Sciences of the Universe [physics]/Earth Sciences/Glaciology
Abstract: International audience; The reconstruction of the largest ice stream to drain the British-Irish Ice Sheet at the Last Glacial Maximum (LGM) can provide essential palaeoglacial observations required for constraining numerical ice sheet models. The Irish Sea Ice Stream (ISIS) was long considered to have terminated on the mid-shelf of the Celtic Sea, based on sediment cores and seismic data collected in the 1970s. Here we summarise findings from sediment cores and geophysical data acquired since 2009, and multi-beam bathymetric data acquired since 2001, which permit an updated evolution and palaeoglacial reconstruction of the Irish and UK sectors of the Celtic Sea shelf. In near-shore areas, multi-beam data reveal over 2000 glacial features, including moraine ridges, streamlined bedrock and meltwater channels, recording the southwest advance of the ISIS towards the shelf-edge and its subsequent retreat. The mid- to outer-shelf is characterised by the largest known linear shelf sediment ridges. These vary from long and linear features, the megaridges, in the northwest to sinuous and shorter ridges in the southeast. This ridge field was initially interpreted as tidal in origin, but glacigenic sediments have been recovered from the flanks of the megaridges. Correlating decimetric-resolution geophysical data to sediment cores, the megaridges comprise three main units. 1) A superficial fining-upward drape above an unconformity, inferred to record decreasing ocean energy during marine transgression. Underlying this drape is 2), the Melville Formation (MFm), which comprises the upper bulk of the megaridges, displaying dipping internal acoustic reflections and consisting of medium to coarse sand and gravel, characteristics that could be consistent with either a tidal or glacifluvial origin. The MFm unconformably overlies 3), the Upper Little Sole Formation (ULSFm), previously proposed to be of late Pliocene to early Pleistocene age, but is here shown to contain glacigenic sediments dated to the LGM. This stratigraphy constrains the age of the MFm to between 24-14 ka BP, coeval with deglaciation and a modelled period of megatidal conditions during transgression. Stratigraphically and sedimentologically these megaridges could represent glacifluvial features eroded during the post-glacial marine transgression. However, it is argued that they comprise a partially-eroded glacial topography (ULSFm) mantled by post-glacial tidal deposits (MFm), both subsequently eroded by a proposed mechanism of enhanced wave energy during decreasing tidal energy in the later stages of transgression. Regardless of the origin of the ridges, the evidence shows that the ISIS extended to the shelf-edge of the Irish and UK sectors during the LGM.
Published: 2019

6. Maximum extent and readvance dynamics of the Irish Sea Ice Stream since the Last Glacial Maximum

Author: Scourse, James, Chiverrell, Richard C., SMALL, DAVID, Smedley, Rachel, Medialdea, Alicia, Burke, Matt, Saher, Margot, Callard, Louise, Van Landeghem, Katrien J.J., Duller, Geoff, Fabel, Derek, Moreton, Steve, Lockhart, Edward, Jenkins, Geraint, Praeg, D, Bateman, Mark, Evans, David, Roberts, Dave, McCarron, Stephen, Wilson, Peter, Livingstone, Stephen, Clark, Chris, University of Liverpool, Durham University, University of Sheffield [Sheffield], School of Ocean Sciences [Menai Bridge], Bangor University, Department of Geography (UNIVERSITé DE DURHAM), Aberystwyth University, University of Glasgow, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Universidade Federal Fluminense [Rio de Janeiro] (UFF), Department of Geography [Sheffield], Department of Geography [Maynooth], National University of Ireland Maynooth (Maynooth University), University of Ulster, European Project: 656821,H2020,H2020-MSCA-IF-2014,SEAGAS(2016), International Union for Quaternary Research (20th Congress), School of Ocean Sciences [Bangor], Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), and National University of Ireland Maynooth (NUIM)
Subjects: [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology
Abstract: International audience; The Irish Sea Ice Stream (ISIS) has long had one of the best documented retreat histories of the British-Irish Ice Sheet (BIIS) and was the first ice stream to be constrained by Bayesian analysis of geochronological data. These attributes made it a model system for the BRITICE-CHRONO research project, which aims to produce the best constrained retreat record of any palaeo-ice sheet contributing key observational constraints for ice sheet modelling. The project has generated a suite of new radiocarbon ages from deglacial sequences offshore in the Celtic and Irish seas and terrestrial cosmogenic nuclide and optically-stimulated luminescence ages from ice-marginal sites in the Isles of Scilly, Ireland, Wales and NW England. The ISIS was unusual within the former BIIS, in that it was a compound ice stream with two outlets, one marine terminating that flowed through the Irish Sea Basin into the Celtic Sea, and a terrestrial terminus that flowed southwards through Cheshire-Shropshire lowlands into the English Midlands around 25.5 ka. Here we assess the retreat dynamics across the entirety of the ISIS, integrating the new chronology in a revised Bayesian analysis that constrains the pattern and timing ice marginal fluctuations. The retreat chronology in the Irish Sea is better constrained than in the Celtic Sea, where the ISIS is now recognised to have extended as far as the continental shelf break to the SW of Britain and Ireland between 24 and 27 ka; this advance was synchronous with independently-dated ice-rafted detritus from ISIS in adjacent deep-sea cores. The ISIS then retreated rapidly northwards through the Celtic Sea, with evidence for readvance phases, deglaciating the Isles of Scilly at 25.5 ka, reaching St Georges Channel by 24.3 ka and the Llŷn Peninsula by 23.9 ka. The initiation of retreat from both the eastern (terrestrial) and western (marine) components of ISIS was synchronous. The eastern terrestrial lobe had vacated the Cheshire-Shropshire lowlands by 22-21 ka. The complex readvance sequences identified on the Llŷn (24-20ka) and in eastern Ireland have now been tightly constrained to register centennial-scale oscillations of the ice front driven by internal ice dynamics over topographic pinning points and constrictions of the ice-stream. Retreat northwards into the northern Irish Sea then accelerated, first evacuating the deeper water of the western Irish Sea, and developing pronounced ice margins across the northern Isle of Man by 19.1 ka. The final retreat phase, with ice margins pulling back onto terrestrial settings in the English Lake District, the north of Ireland and SW Scotland around 17 ka, was a deglaciation accomplished in a fully marine context evidenced by the preservation on the seabed of subglacial landforms and by increasing influence of local ice sources with flow realignment during draw-down and ice margin retreat.
Published: 2019

7. Mid-Devensian climate and landscape in England: new data from Finningley, South Yorkshire

Author: Malcolm T. Greenwood, Philip I. Buckland, Mark D. Bateman, Paul C. Buckland, Julian B. Murton, Charles D. Frederick, Della K. Murton, Eva Panagiotakopulu, Brian M. Chase, Ole Bennike, Department of Geography [Sheffield], University of Sheffield [Sheffield], Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de recherche pour le développement [IRD] : UR226, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS)
Subjects: Marine isotope stage, 010506 paleontology, Climate Research, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Permafrost, 01 natural sciences, Klimatforskning, Periglaciation, mid-Devensian, Earth Science, Glacial period, Stadial, plant macrofossils, lcsh:Science, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Vale of York, periglaciation, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Ekologi, geography, Multidisciplinary, geography.geographical_feature_category, Ecology, Trichoptera, Geovetenskap och miljövetenskap, Macrofossil, Geology, Tundra, Coleoptera, Arctic, 13. Climate action, lcsh:Q, Geologi, Physical geography, Earth and Related Environmental Sciences, Research Article
Abstract: While there is extensive evidence for the Late Devensian, less is known about Early and Middle Devensian (approx. 110–30 ka) climates and environments in the UK. The Greenland ice-core record suggests the UK should have endured multiple changes, but the terrestrial palaeo-record lacks sufficient detail for confirmation from sites in the British Isles. Data from deposits at Finningley, South Yorkshire, can help redress this. A channel with organic silts, dated 40 314–39 552 cal a BP, contained plant macrofossil and insect remains showing tundra with dwarf-shrub heath and bare ground. Soil moisture conditions varied from free draining to riparian, with ponds and wetter vegetated areas. The climate was probably low arctic with snow cover during the winter. Mutual climatic range (MCR), based on Coleoptera, shows the mean monthly winter temperatures of −22 to −2°C and summer ones of 8–14°C. Periglacial structures within the basal gravel deposits and beyond the glacial limits indicate cold-climate conditions, including permafrost. A compilation of MCR reconstructions for other Middle Devensian English sites shows that marine isotope stage 3—between 59 and 28 ka—experienced substantial variation in climate consistent with the Greenland ice-core record. The exact correlation is hampered by temporal resolution, but the Finningley site stadial at approximately 40 ka may correlate with the one of the Greenland stadials 7–11.
Published: 2019
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8. Advance and retreat of the marine-terminating Irish Sea Ice Stream into the Celtic Sea during the Last Glacial: Timing and maximum extent

Author: Scourse, James, Saher, Margot, Van Landeghem, Katrien J.J., Lockhart, Edward, Purcell, Catriona, Callard, Louise, Roseby, Zoe, Allinson, Ben, Pieńkowski, Anna J., O'Cofaigh, Colm, Praeg, Daniel, Ward, Sophie, Chiverrell, Richard, Moreton, Steve, Fabel, Derek, Clark, Chris D., College of Life and Environmental Sciences [Exeter], University of Exeter, School of Ocean Sciences [Menai Bridge], Bangor University, Department of Geography, Durham University, University of Southampton, The University Centre in Svalbard (UNIS), Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Laboratório de Geologia Marinha (LAGEMAR), Universidade Federal Fluminense [Rio de Janeiro] (UFF), University College of London [London] (UCL), School of Environmental Sciences [Liverpool], University of Liverpool, Scottish Universities Environmental Research Centre (SUERC), University of Glasgow-University of Edinburgh, Department of Geography [Sheffield], and University of Sheffield [Sheffield]
Subjects: Europe, Quaternary stratigraphy, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDU.STU.ST]Sciences of the Universe [physics]/Earth Sciences/Stratigraphy, Shelf (morphology and stratigraphy), Glacial sediments, Geophysics (seismic), [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, Micropaleontology (forams), [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography
Abstract: International audience; The dynamics of the British-Irish Ice Sheet (BIIS) during the Last Glacial were conditioned by marine-based ice streams, the largest of which by far was the Irish Sea Ice Stream (ISIS) which drained southwest across the Celtic shelf. The maximum extent and timing of the ISIS have been constrained by onshore evidence from the UK and Ireland, and by glacigenic sediments encountered in a small suite of vibrocores from the UK-Irish continental shelf, from which a single radiocarbon date is available. These data have long supported ice advance to at least the mid-shelf, while recent results suggest the ISIS may have extended 150 km farther seaward to the shelf edge. The glacigenic sequences have not been placed within a secure seismic-stratigraphic context and the relationship between glaciation and the linear sediment megaridges observed on the outer shelf of the Celtic Sea has remained uncertain. Here we report results of sedimentological, geochemical, geochronological and micro-palaeontological analyses combined with a seismic-stratigraphic investigation of the glacigenic sequences of the Celtic Sea with the aims of establishing maximum extent, depositional context, timing and retreat chronology of ISIS. Eight lithofacies packages are identified, six of which correlate with seismic facies. Lithofacies LF1 and LF2 correlate to a seafloor seismic facies (SF1) that we interpret to record the postglacial and Holocene transgressive flooding of the shelf. Lithofacies LF10 (till), LF3, LF4 and LF8 (glacimarine) correlate to different seismic facies that we interpret to be of glacigenic origin based on sedimentological, geotechnical and micropalaeontological evidence, and their distribution, supported by geochemical evidence from lithofacies LF8 and LF10 indicate extension of ISIS as far as the Celtic Sea shelf break. New radiocarbon ages on calcareous micro-and macrofauna constrain this advance to be between 24 and 27 cal ka BP, consistent with pre-existing geochronological constraints. Glacimarine lithofacies LF8 is in places glacitectonically contorted and deformed, indicating ice read-vance, but the nature and timing of this readvance is unclear. Retreat out of the Celtic Sea was initially rapid and may have been triggered by high relative sea-levels driven by significant glacio-isostatic depression, consistent with greater ice loads over Britain and Ireland than previously considered.
Published: 2019
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9. A stratigraphic investigation of the Celtic Sea megaridges based on seismic and core data from the Irish-UK sectors

Author: C.L. Mellett, James D. Scourse, Daniel Praeg, Margot Saher, Louise Callard, Katrien J.J. Van Landeghem, Chris D. Clark, Edward Lockhart, Sara Benetti, Richard C. Chiverrell, Colm Ó Cofaigh, School of Ocean Sciences [Menai Bridge], Bangor University, University of Exeter, Istituto Nazionale di Geofisica e di Oceanografia Sperimentale (OGS), Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), British Geological Survey [Edinburgh], British Geological Survey (BGS), Wessex Archaeology [Salisbury], Department of Geography (UNIVERSITé DE DURHAM), Durham University, Department of Geography and Planning, University of Liverpool, School of Geography and Environmental Sciences, University of Ulster, Department of Geography [Sheffield], University of Sheffield [Sheffield], and COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])
Subjects: 010506 paleontology, Archeology, Global and Planetary Change, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Pleistocene, Continental shelf, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Geology, 01 natural sciences, Unconformity, Paleontology, Stratigraphy, Deglaciation, 14. Life underwater, Glacial period, Ecology, Evolution, Behavior and Systematics, Holocene, 0105 earth and related environmental sciences, Marine transgression
Abstract: International audience; The Celtic Sea contains the world's largest continental shelf sediment ridges. These megaridges were initially interpreted as tidal features formed during post-glacial marine transgression, but glacigenic sediments have been recovered from their flanks. We examine the stratigraphy of the megaridges using new decimetric-resolution geophysical data correlated to sediment cores to test hypothetical tidal vs glacial modes of formation. The megaridges comprise three main units, 1) a superficial fining-upward drape that extends across the shelf above an unconformity. Underlying this drape is 2), the Melville Formation (MFm) which comprises the upper bulk of the megaridges, sometimes displaying dipping internal acoustic reflections and consisting of medium to coarse sand and shell fragments; characteristics consistent with either a tidal or glacifluvial origin. The MFm unconformably overlies 3), the Upper Little Sole Formation (ULSFm), previously interpreted to be of late Pliocene to early Pleistocene age, but here shown to correlate to Late Pleistocene glacigenic sediments forming a precursor topography. The superficial drape is interpreted as a product of prolonged wave energy as tidal currents diminished during the final stages of post-glacial marine transgression. We argue that the stratigraphy constrains the age of the MFm to between 24.3 and 14 ka BP, based on published dates, coeval with deglaciation and a modelled period of megatidal conditions during post-glacial marine transgression. Stratigraphically and sedimentologically, the megaridges could represent preserved glacifluvial features, but we suggest that they comprise post-glacial tidal deposits (MFm) mantling a partially-eroded glacial topography (ULSFm). The observed stratigraphy suggests that ice extended to the continental shelf-edge.
Published: 2018
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10. Features caused by ground ice growth and decay in Late Pleistocene fluvial deposits, Paris Basin, France

Author: Mark D. Bateman, Eric Andrieux, Marianne Font, Deborah Sicilia, Kevin Manchuel, Pascal Bertran, Institut national de recherches archéologiques préventives (Inrap), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Department of Geography [Sheffield], University of Sheffield [Sheffield], Morphodynamique Continentale et Côtière (M2C), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), and EDF (EDF)
Subjects: 010506 paleontology, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Pleistocene, Last glacial, Faulting, Fluvial, Permafrost, 15. Life on land, 01 natural sciences, Ice wedge, Thermokarst, Paleontology, 13. Climate action, Paris Basin, Marl, Thermokarst lakes, Glacial period, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, Slumping, Geology, 0105 earth and related environmental sciences, Earth-Surface Processes
Abstract: (IF 3.68; Q1); International audience; Last Glacial fluvial sequences in the Paris Basin show laminated lacustrine deposits OSL and radiocarbon dated to between 24.6 and 16.6 ka in one site and overlying alluvial sandy gravel. A thermokarst origin of the lakes is supported by abundant traces of ground ice, particularly ice wedge pseudomorphs beneath the lacustrine layers and synsedimentary deformation caused by thaw settlement. The features include brittle deformation (normal and reverse faults) resulting from ground subsidence owing to ice melting and ductile deformations caused by slumping of the sediments heaved by the growth of ice-cored mounds. These correspond to lithalsas (or lithalsa plateaus) and/or to open system pingos. At least two generations of thermokarst are recorded and may reflect the millennial climate variability typical of the Last Glacial. The structures studied in quarries are associated with an undulating topography visible in 5-m DEMs and a spotted pattern in aerial photographs. The search for similar patterns in the Paris Basin indicates that many other potential thermokarst sites exist in the Last Glacial terrace (Fy) of rivers located north of 48°N when they cross the lower Cretaceous sands and marls. In some sites, the presence of organic-poor, fine-grained deposits presumably of lacustrine origin was confirmed by borehole data. The site distribution coincides broadly with that already known for ice wedge pseudomorphs. This study provides new evidence of permafrost-induced ground deformations in France and strongly suggests that thermokarst played a significant and probably largely underestimated role in the genesis of Late Pleistocene landscapes.
Published: 2018
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11. The chronology of Late Pleistocene thermal contraction cracking derived from sand wedge OSL dating in central and southern France

Author: Mark D. Bateman, Pascal Bertran, Eric Andrieux, De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Department of Geography [Sheffield], University of Sheffield [Sheffield], and Institut national de recherches archéologiques préventives (Inrap)
Subjects: Sand wedge, 010506 paleontology, Global and Planetary Change, 010504 meteorology & atmospheric sciences, Pleistocene, Thermoluminescence dating, Optically stimulated luminescence, Luminescence dating, Oceanography, Permafrost, 01 natural sciences, Paleontology, Thermal contraction cracking, Aeolian processes, Younger Dryas, France, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, OSL, Quaternary, Geology, 0105 earth and related environmental sciences, Chronology
Abstract: International audience; Much of France remained unglaciated during the Late Quaternary and was subjected to repeated phases of periglacial activity. Numerous periglacial features have been reported but disentangling the environmental and climatic conditions they formed under, the timing and extent of permafrost and the role of seasonal frost has remained elusive. The primary sandy infillings of relict sand-wedges and composite-wedge pseudomorphs record periglacial activity. As they contain well-bleached quartz-rich aeolian material they are suitable for optically stimulated luminescence dating (OSL). This study aims to reconstruct when wedge activity took place in two regions of France; Northern Aquitaine and in the Loire valley. Results from single-grain OSL measurements identify multiple phases of activity within sand wedges which suggest that wedge activity in France occurred at least 11 times over the last 100 ka. The most widespread events of thermal contraction cracking occurred between ca. 30 and 24 ka (Last Permafrost Maximum) which are concomitant with periods of high sand availability (MIS 2). Although most phases of sand-wedge growth correlate well with known Pleistocene cold periods, the identification of wedge activity during late MIS 5 and the Younger Dryas strongly suggests that these features do not only indicate permafrost but also deep seasonal ground freezing in the context of low winter insolation. These data also suggest that the overall young ages yielded by North-European sand-wedges likely result from poor record of periglacial periods concomitant with low sand availability and/or age averaging inherent with standard luminescence methods.
Published: 2018
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12. The Greenland and Antarctic ice sheets under 1.5 °C global warming

Author: Gaël Durand, Michiel R. van den Broeke, Nicholas R. Golledge, Xavier Fettweis, Xylar Asay-Davis, Heiko Goelzer, Frank Pattyn, Lionel Favier, Luke D. Trusel, Alexander Robinson, Catherine Ritz, Peter Kuipers Munneke, Antony J. Payne, Jan T. M. Lenaerts, Helene Seroussi, Edward Hanna, Rob DeConto, Sophie Nowicki, Laboratoire de Glaciologie [Bruxelles], Université libre de Bruxelles (ULB), Observatoire des Sciences de l'Univers de Grenoble (OSUG ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Geography [Sheffield], University of Sheffield [Sheffield], Institut des Géosciences de l’Environnement (IGE), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire sols, solides, structures - risques [Grenoble] (3SR ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Département de Géographie, Université de Liège, Institute for Marine and Atmospheric Research [Utrecht] (IMAU), Utrecht University [Utrecht], Laboratoire de mécanique des sols, structures et matériaux (MSSMat), CentraleSupélec-Centre National de la Recherche Scientifique (CNRS), Université Libre de Bruxelles [Bruxelles] (ULB), EDGe, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Laboratoire sols, solides, structures - risques [Grenoble] (3SR), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut National Polytechnique de Grenoble (INPG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Centre National de la Recherche Scientifique (CNRS)-CentraleSupélec, Sub Dynamics Meteorology, and Marine and Atmospheric Research
Subjects: 010504 meteorology & atmospheric sciences, Drainage basin, Forcing (mathematics), Environmental Science (miscellaneous), 010502 geochemistry & geophysics, 01 natural sciences, F860 Climatology, medicine, [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology, ComputingMilieux_MISCELLANEOUS, Collapse (medical), 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Global warming, Lead (sea ice), Glaciologie, [SDU]Sciences of the Universe [physics], 13. Climate action, Climatology, Ice sheet, medicine.symptom, Surface mass, Geology, Social Sciences (miscellaneous)
Abstract: Even if anthropogenic warming were constrained to less than 2 °C above pre-industrial, the Greenland and Antarctic ice sheets will continue to lose mass this century, with rates similar to those observed over the past decade. However, nonlinear responses cannot be excluded, which may lead to larger rates of mass loss. Furthermore, large uncertainties in future projections still remain, pertaining to knowledge gaps in atmospheric (Greenland) and oceanic (Antarctica) forcing. On millennial timescales, both ice sheets have tipping points at or slightly above the 1.5–2.0 °C threshold; for Greenland, this may lead to irreversible mass loss due to the surface mass balance–elevation feedback, whereas for Antarctica, this could result in a collapse of major drainage basins due to ice-shelf weakening., SCOPUS: re.j, info:eu-repo/semantics/published
Published: 2018
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13. Assessing recent trends in high-latitude Southern Hemisphere surface climate

Author: Xavier Crosta, Julie M. Jones, Nerilie J. Abram, Adele K. Morrison, Matthew H. England, Hugues Goosse, Anais Orsi, Kyle R. Clem, Eric J. Steig, Tessa Vance, Sarah T. Gille, James A. Renwick, Dan J. Charman, Ryan L. Fogt, Marilyn N. Raphael, Pablo O. Canziani, Graham Simpkins, Casimir de Lavergne, Leela M. Frankcombe, Barbara Stenni, David P. Schneider, Gareth J. Marshall, Ian Eisenman, Didier Swingedouw, Valérie Masson-Delmotte, Department of Geography [Sheffield], University of Sheffield [Sheffield], Scripps Institution of Oceanography (SIO), University of California [San Diego] (UC San Diego), University of California-University of California, Institut d'Astronomie et de Géophysique Georges Lemaître (UCL-ASTR), Université Catholique de Louvain = Catholic University of Louvain (UCL), Australian National University (ANU), Environnements et Paléoenvironnements OCéaniques (EPOC), Observatoire aquitain des sciences de l'univers (OASU), Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Computing, Electronics and Mathematics [Coventry], Faculty of Engineering, Environment and Computing [Coventry], Coventry University -Coventry University, Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette] (LSCE), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), Glaces et Continents, Climats et Isotopes Stables (GLACCIOS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ), National Center for Atmospheric Research [Boulder] (NCAR), University of Ca’ Foscari [Venice, Italy], Scripps Institution of Oceanography (SIO - UC San Diego), University of California (UC)-University of California (UC), Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Sciences et Technologies - Bordeaux 1 (UB)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-École Pratique des Hautes Études (EPHE), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010504 meteorology & atmospheric sciences, Environmental Science (miscellaneous), Social Sciences (miscellaneous), Environmental Science and Management, CLIMATE CHANGE, Magnitude (mathematics), Climate change, Context (language use), Forcing (mathematics), 010502 geochemistry & geophysics, 01 natural sciences, Physical Geography and Environmental Geoscience, Ciencias de la Tierra y relacionadas con el Medio Ambiente, Atmospheric Sciences, Investigación Climatológica, Atmosphere, CLIMATE VARIABILITY, 14. Life underwater, Southern Hemisphere, [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Mode (statistics), Climate Action, ANTARCTICA, 13. Climate action, Settore GEO/08 - Geochimica e Vulcanologia, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, Climatology, Environmental science, Climate model, CIENCIAS NATURALES Y EXACTAS
Abstract: Understanding the causes of recent climatic trends and variability in the high-latitude Southern Hemisphere is hampered by a short instrumental record. Here, we analyse recent atmosphere, surface ocean and sea-ice observations in this region and assess their trends in the context of palaeoclimate records and climate model simulations. Over the 36-year satellite era, significant linear trends in annual mean sea-ice extent, surface temperature and sea-level pressure are superimposed on large interannual to decadal variability. Most observed trends, however, are not unusual when compared with Antarctic palaeoclimate records of the past two centuries. With the exception of the positive trend in the Southern Annular Mode, climate model simulations that include anthropogenic forcing are not compatible with the observed trends. This suggests that natural variability overwhelms the forced response in the observations, but the models may not fully represent this natural variability or may overestimate the magnitude of the forced response. Fil: Jones, Julie. University of Sheffield; Reino Unido Fil: Gille, Sarah. University of California at San Diego. Scripps Institution of Oceanography; Estados Unidos Fil: Goose, Hugues J.. Université Catholique de Louvain; Bélgica Fil: Abram, Nerillie J.. The Australian National University; Australia Fil: Canziani, Pablo Osvaldo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Tecnológica Nacional. Facultad Regional Buenos Aires. Unidad de Investigación y Desarrollo de las Ingenierías; Argentina Fil: Charman, Dan J.. University of Exeter; Reino Unido Fil: Clem, Kyle R.. Victoria University of Wellington; Nueva Zelanda Fil: Crosta Xavier. Universite de Bordeaux; Francia Fil: de Lavergne, Casimir. Université Pierre et Marie Curie; Francia Fil: Eisenman, Ian. University of California at San Diego. Scripps Institution of Oceanography; Estados Unidos Fil: England, Matthew H.. University of New South Wales; Australia Fil: Fogt, Ryan L.. Ohio University; Estados Unidos Fil: Frankcombe, Leela M.. University of New South Wales; Australia Fil: Marshall, Gareth J.. British Antartic Survey; Reino Unido Fil: Masson Delmotte, Valérie. Université de Paris-Saclay; Francia. Centre National de la Recherche Scientifique; Francia Fil: Morrison, Adele K.. University of Princeton; Estados Unidos Fil: Orsi, Anaïs J.. Université de Paris-Saclay; Francia Fil: Raphael, Marilyn N.. University of California; Estados Unidos Fil: Renwick, James A.. Victoria University of Wellington; Nueva Zelanda Fil: Schneider, David P.. National Center for Atmospheric Research; Estados Unidos Fil: Simpkins, Graham R.. University of California at Irvine. School of Physical Sciences. Department of Earth System Sciences; Estados Unidos Fil: Steig, Eric J.. University of Washington; Estados Unidos Fil: Steni, Barbara. Universita' Ca' Foscari Di Venezia; Italia Fil: Swingedow, Didier. Universite de Bordeaux; Francia Fil: Vance, Tessa R.. Antarctic Climate and Ecosystems Cooperative Research Centre; Australia
Published: 2016
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14. Decadal slowdown of a land-terminating sector of the Greenland Ice Sheet despite warming

Author: Andrew J. Tedstone, Noel Gourmelen, Daniel Goldberg, Peter Nienow, Edward Hanna, Amaury Dehecq, School of Geosciences [Edinburgh], University of Edinburgh, Laboratoire d'Informatique, Systèmes, Traitement de l'Information et de la Connaissance (LISTIC), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry]), Department of Geography [Sheffield], and University of Sheffield [Sheffield]
Subjects: geography, Multidisciplinary, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, [SDE.MCG]Environmental Sciences/Global Changes, Ice stream, Greenland ice sheet, Antarctic sea ice, 010502 geochemistry & geophysics, 01 natural sciences, Arctic ice pack, Ice-sheet model, Oceanography, 13. Climate action, Climatology, Sea ice, Ice sheet, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, Meltwater, Geology, 0105 earth and related environmental sciences
Abstract: International audience; Ice flow along land-terminating margins of the Greenland Ice Sheet (GIS) varies considerably in response to fluctuating inputs of surface meltwater to the bed of the ice sheet. Such inputs lubricate the ice–bed interface, transiently speeding up the flow of ice1, 2. Greater melting results in faster ice motion during summer, but slower motion over the subsequent winter, owing to the evolution of an efficient drainage system that enables water to drain from regions of the ice-sheet bed that have a high basal water pressure2, 3. However, the impact of hydrodynamic coupling on ice motion over decadal timescales remains poorly constrained. Here we show that annual ice motion across an 8,000-km2 land-terminating region of the west GIS margin, extending to 1,100 m above sea level, was 12% slower in 2007–14 compared with 1985–94, despite a 50% increase in surface meltwater production. Our findings suggest that, over these three decades, hydrodynamic coupling in this section of the ablation zone resulted in a net slowdown of ice motion (not a speed-up, as previously postulated1). Increases in meltwater production from projected climate warming may therefore further reduce the motion of land-terminating margins of the GIS. Our findings suggest that these sectors of the ice sheet are more resilient to the dynamic impacts of enhanced meltwater production than previously thought.
Published: 2015
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15. NEMO–ICB (v1.0): interactive icebergs in the NEMO ocean model globally configured at eddy-permitting resolution

Author: Adam T. Blaker, S.G. Alderson, Robert Marsh, Bablu Sinha, Vladimir Zalesny, Vladimir Ivchenko, Nikolaos Skliris, Andrew C. Coward, J. Le Sommer, Yevgeny Aksenov, N. Merino, Gurvan Madec, Grant R. Bigg, University of Southampton, National Oceanography Centre (NOC), Department of Geography [Sheffield], University of Sheffield [Sheffield], Nucleus for European Modeling of the Ocean (NEMO R&D ), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Institute for Numerical Mathematics, Russian Academy of Sciences, Moscow, Russian Federation, Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Drift ice, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, 010505 oceanography, lcsh:QE1-996.5, [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Antarctic sea ice, 01 natural sciences, Iceberg, Marine Sciences, lcsh:Geology, Oceanography, Fast ice, 13. Climate action, Sea ice thickness, [SDE]Environmental Sciences, Sea ice, Thermohaline circulation, 14. Life underwater, Sea ice concentration, Geology, 0105 earth and related environmental sciences
Abstract: An established iceberg module, ICB, is used interactively with the Nucleus for European Modelling of the Ocean (NEMO) ocean model in a new implementation, NEMO–ICB (v1.0). A 30-year hindcast (1976–2005) simulation with an eddy-permitting (0.25°) global configuration of NEMO–ICB is undertaken to evaluate the influence of icebergs on sea ice, hydrography, mixed layer depths (MLDs), and ocean currents, through comparison with a control simulation in which the equivalent iceberg mass flux is applied as coastal runoff, a common forcing in ocean models. In the Southern Hemisphere (SH), drift and melting of icebergs are in balance after around 5 years, whereas the equilibration timescale for the Northern Hemisphere (NH) is 15–20 years. Iceberg drift patterns, and Southern Ocean iceberg mass, compare favourably with available observations. Freshwater forcing due to iceberg melting is most pronounced very locally, in the coastal zone around much of Antarctica, where it often exceeds in magnitude and opposes the negative freshwater fluxes associated with sea ice freezing. However, at most locations in the polar Southern Ocean, the annual-mean freshwater flux due to icebergs, if present, is typically an order of magnitude smaller than the contribution of sea ice melting and precipitation. A notable exception is the southwest Atlantic sector of the Southern Ocean, where iceberg melting reaches around 50% of net precipitation over a large area. Including icebergs in place of coastal runoff, sea ice concentration and thickness are notably decreased at most locations around Antarctica, by up to ~ 20% in the eastern Weddell Sea, with more limited increases, of up to ~ 10% in the Bellingshausen Sea. Antarctic sea ice mass decreases by 2.9%, overall. As a consequence of changes in net freshwater forcing and sea ice, salinity and temperature distributions are also substantially altered. Surface salinity increases by ~ 0.1 psu around much of Antarctica, due to suppressed coastal runoff, with extensive freshening at depth, extending to the greatest depths in the polar Southern Ocean where discernible effects on both salinity and temperature reach 2500 m in the Weddell Sea by the last pentad of the simulation. Substantial physical and dynamical responses to icebergs, throughout the global ocean, are explained by rapid propagation of density anomalies from high-to-low latitudes. Complementary to the baseline model used here, three prototype modifications to NEMO–ICB are also introduced and discussed.
Published: 2015
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16. Nitrate postdeposition processes in Svalbard surface snow

Author: Bjorkman, M.P., Carmen P. Vega, Kuhnel, Spataro, Ianniello, Esposito, Kaiser, Marca, Hodson, Isaksson, Tjarda J.R., Department of Geosciences [Oslo], Faculty of Mathematics and Natural Sciences [Oslo], University of Oslo (UiO)-University of Oslo (UiO), Norwegian Polar Institute, Department of Earth Sciences - Palaeobiology [Uppsala], Uppsala University, Istituto sull’Inquinamento Atmosferico (CNR-IIA), Consiglio Nazionale delle Ricerche (CNR), School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), Department of Geography [Sheffield], University of Sheffield [Sheffield], Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Arctic Field Grant, Svalbard Science Forum, ANR-10-LABX-0100,VOLTAIRE,Geofluids and Volatil elements – Earth, Atmosphere, Interfaces – Resources and Environment(2010), European Project: 215503,EC:FP7:PEOPLE,FP7-PEOPLE-2007-1-1-ITN,NSINK(2008), and National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Reactive nitrogen, snow chemistry, nitrate, postdeposition, BrO chemistry, photolysis, Svalbard, Planetary boundary layer, 010501 environmental sciences, Atmospheric sciences, 01 natural sciences, Sink (geography), chemistry.chemical_compound, Nitrate, Ice core, Earth and Planetary Sciences (miscellaneous), 0105 earth and related environmental sciences, geography, geography.geographical_feature_category, Geovetenskap och miljövetenskap, Snowpack, Snow, Geophysics, chemistry, 13. Climate action, Space and Planetary Science, [SDU]Sciences of the Universe [physics], Snowmelt, Environmental science, Earth and Related Environmental Sciences, human activities
Abstract: International audience; The snowpack acts as a sink for atmospheric reactive nitrogen, but several postdeposition pathways have been reported to alter the concentration and isotopic composition of snow nitrate with implications for atmospheric boundary layer chemistry, ice core records, and terrestrial ecology following snow melt. Careful daily sampling of surface snow during winter (11–15 February 2010) and springtime (9 April to 5 May 2010) near Ny-Ålesund, Svalbard reveals a complex pattern of processes within the snowpack. Dry deposition was found to dominate over postdeposition losses, with a net nitrate deposition rate of (0.6 ± 0.2) μmol m À2 d À1 to homogeneous surface snow. At Ny-Ålesund, such surface dry deposition can either solely result from long-range atmospheric transport of oxidized nitrogen or include the redeposition of photolytic/bacterial emission originating from deeper snow layers. Our data further confirm that polar basin air masses bring 15 N-depleted nitrate to Svalbard, while high nitrate δ(18 O) values only occur in connection with ozone-depleted air, and show that these signatures are reflected in the deposited nitrate. Such ozone-depleted air is attributed to active halogen chemistry in the air masses advected to the site. However, here the Ny-Ålesund surface snow was shown to have an active role in the halogen dynamics for this region, as indicated by declining bromide concentrations and increasing nitrate δ(18 O), during high BrO (low-ozone) events. The data also indicate that the snowpack BrO-NO x cycling continued in postevent periods, when ambient ozone and BrO levels recovered.
Published: 2014
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17. Nitrate dry deposition in Svalbard

Author: Andy Hodson, Mauro Mazzola, Elisabeth Isaksson, Rafael Kühnel, Johan Ström, Mats P. Björkman, Wenche Aas, Daniel G. Partridge, Angelo Viola, Tjarda Roberts, Norwegian Polar Institute, Stockholm University, Laboratoire de Physique et Chimie de l'Environnement et de l'Espace (LPC2E), Observatoire des Sciences de l'Univers en région Centre (OSUC), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université d'Orléans (UO)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Norwegian Institute for Air Research (NILU), Istituto di Scienze dell'Atmosfera e del Clima (ISAC), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Department of Geography [Sheffield], University of Sheffield [Sheffield], European Project: 215503,EC:FP7:PEOPLE,FP7-PEOPLE-2007-1-1-ITN,NSINK(2008), and Consiglio Nazionale delle Ricerche [Roma] (CNR)
Subjects: Atmospheric Science, 010504 meteorology & atmospheric sciences, Reactive nitrogen, chemistry.chemical_element, 010501 environmental sciences, lcsh:QC851-999, snow, boundary layer, Atmospheric sciences, 01 natural sciences, Atmosphere, chemistry.chemical_compound, Arctic, Nitrate, Precipitation, 0105 earth and related environmental sciences, [SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], arctic, Ny-Ålesund, deposition velocity, nitric acid, 15. Life on land, Snow, atmospheric chemistry, snow chemistry, aerosol science, Nitrogen, Deposition (aerosol physics), chemistry, 13. Climate action, lcsh:Meteorology. Climatology
Abstract: Arctic regions are generally nutrient limited, receiving an extensive part of their bio-available nitrogen from the deposition of atmospheric reactive nitrogen. Reactive nitrogen oxides, as nitric acid (HNO 3 ) and nitrate aerosols (p-NO 3 ), can either be washed out from the atmosphere by precipitation or dry deposited, dissolving to nitrate ( ). During winter, is accumulated in the snowpack and released as a pulse during spring melt. Quantification of deposition is essential to assess impacts on Arctic terrestrial ecology and for ice core interpretations. However, the individual importance of wet and dry deposition is poorly quantified in the high Arctic regions where in-situ measurements are demanding. In this study, three different methods are employed to quantify dry deposition around the atmospheric and ecosystem monitoring site, Ny-Alesund, Svalbard, for the winter season (September 2009 to May 2010): (1) A snow tray sampling approach indicates a dry deposition of –10.27±3.84 mg m −2 (± S.E.); (2) A glacial sampling approach yielded somewhat higher values –30.68±12.00 mg m −2 ; and (3) Dry deposition was also modelled for HNO 3 and p-NO 3 using atmospheric concentrations and stability observations, resulting in a total combined nitrate dry deposition of –10.76±1.26 mg m −2 . The model indicates that deposition primarily occurs via HNO 3 with only a minor contribution by p-NO 3 . Modelled median deposition velocities largely explain this difference: 0.63 cm s −1 for HNO 3 while p-NO 3 was 0.0025 and 0.16 cm s −1 for particle sizes 0.7 and 7 µm, respectively. Overall, the three methods are within two standard errors agreement, attributing an average 14% (total range of 2–44%) of the total nitrate deposition to dry deposition. Dry deposition events were identified in association with elevated atmospheric concentrations, corroborating recent studies that identified episodes of rapid pollution transport and deposition to the Arctic. Keywords: snow, Arctic, boundary layer, Ny-Alesund, deposition velocity, nitric acid (Published: 30 January 2013) Citation: Tellus B 2013, 65 , 19071, http://dx.doi.org/10.3402/tellusb.v65i0.19071
Published: 2013
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18. Sustained monitoring of the Southern Ocean at Drake passage: past achievements and future priorities

Author: David P. Marshall, M. A. Morales Maqueda, Grant R. Bigg, Loïc Jullion, Lesley C. Allison, Harry Leach, Brian A. King, Angela Hibbert, Teresa K. Chereskin, Philip L. Woodworth, Yueng-Djern Lenn, Karen J. Heywood, Kathleen A. Donohue, Jean-Baptiste Sallée, Helen L. Johnson, David R. Munday, Andrew McC. Hogg, Chris W. Hughes, Michael P. Meredith, Alberto C. Naveira Garabato, Christine Provost, Janet Sprintall, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), National Oceanography Centre (NOC), Scripps Institution of Oceanography (SIO - UC San Diego), University of California [San Diego] (UC San Diego), University of California (UC)-University of California (UC), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), University of Oxford, Department of Meteorology [Reading], University of Reading (UOR), Department of Geography [Sheffield], University of Sheffield [Sheffield], Graduate School of Oceanography [Narragansett], University of Rhode Island (URI), School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), Department of Earth Ocean and Ecological Sciences [Liverpool], University of Liverpool, Research School of Earth Sciences [Canberra] (RSES), Australian National University (ANU), National Oceanography Centre [Southampton] (NOC), University of Southampton, Bangor University, Austral, Boréal et Carbone (ABC), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Scripps Institution of Oceanography (SIO), University of California-University of California, University of Oxford [Oxford], Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP)-Institut de Recherche pour le Développement (IRD)-Muséum national d'Histoire naturelle (MNHN)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)
Subjects: 010504 meteorology & atmospheric sciences, 010505 oceanography, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], [SDE.MCG]Environmental Sciences/Global Changes, Ocean current, Context (language use), [PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph], Circumpolar star, 01 natural sciences, Lower limb, Marine Sciences, Geophysics, Oceanography, 13. Climate action, Environmental science, 14. Life underwater, 0105 earth and related environmental sciences
Abstract: Paper number: 2010RG000348; International audience; Drake Passage is the narrowest constriction of the Antarctic Circumpolar Current (ACC) in the Southern Ocean, with implications for global ocean circulation and climate. We review the long-term sustained monitoring programs that have been conducted at Drake Passage, dating back to the early part of the twentieth century. Attention is drawn to numerous breakthroughs that have been made from these programs, including (1) the first determinations of the complex ACC structure and early quantifications of its transport; (2) realization that the ACC transport is remarkably steady over interannual and longer periods, and a growing understanding of the processes responsible for this; (3) recognition of the role of coupled climate modes in dictating the horizontal transport and the role of anthropogenic processes in this; and (4) understanding of mechanisms driving changes in both the upper and lower limbs of the Southern Ocean overturning circulation and their impacts. It is argued that monitoring of this passage remains a high priority for oceanographic and climate research but that strategic improvements could be made concerning how this is conducted. In particular, long-term programs should concentrate on delivering quantifications of key variables of direct relevance to large-scale environmental issues: In this context, the time-varying overturning circulation is, if anything, even more compelling a target than the ACC flow. Further, there is a need for better international resource sharing and improved spatiotemporal coordination of the measurements. If achieved, the improvements in understanding of important climatic issues deriving from Drake Passage monitoring can be sustained into the future.
Published: 2011
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19. Du bon usage de la pénurie en eau. Lorraine, 1949-1971

Author: Romain Garcier, Department of Geography [Sheffield], University of Sheffield [Sheffield], and GARCIER, Romain
Subjects: Lorraine, [SHS.GEO] Humanities and Social Sciences/Geography, eau, pollution, [SHS.GEO]Humanities and Social Sciences/Geography, pénurie
Abstract: 18 pages.; Dans les années 1950 et 1960, la Lorraine avait peur de manquer d'eau. Les besoins industriels, la croissance de la population mais aussi l'influence de la pollution laissaient planer le spectre de la pénurie – aujourd'hui bien oublié. La réalité mais aussi le discours de la pénurie ont eu une influence considérable sur les politiques hydrologiques et d'aménagement menées à partir du milieu des années 1960 dans la région. En analysant la genèse et le discours de la pénurie, cet article se propose de montrer que la pénurie a fait l'objet d'un utilisation politique pour convaincre les acteurs régionaux du bien fondé des politiques novatrices menées dans le sillage de la loi sur l'Eau de 1964.
Published: 2009

20. Economic evaluation of nutrition interventions: Does one size fit all?

Author: Fattore G, Federici C, Drummond M, Mazzocchi M, Detzel P, Hutton ZV, and Shankar B
Subjects: Cost-Benefit Analysis, Humans, Nutritional Status, Private Sector
Abstract: Background: Nutrition interventions have specific features that might warrant modifications to the methods used for economic evaluations of healthcare interventions., Aim: The aim of the article is to identify these features and when they challenge the use of cost-utility analysis (CUA)., Methods: A critical review of the literature is conducted and a 2 by 2 classification matrix for nutrition interventions is proposed based on 1) who the main party responsible for the implementation and funding of the intervention is; and 2) who the target recipient of the intervention is. The challenges of conducting economic evaluations for each group of nutrition interventions are then analysed according to four main aspects: attribution of effects, measuring and valuing outcomes, inter-sectorial costs and consequences and equity considerations., Results and Conclusions: CUA is appropriate for nutrition interventions when they are funded from the healthcare sector, have no (or modest) spill-overs to other sectors of the economy and have only (or mainly) health consequences. For other interventions, typically involving different government agencies, with cost implications for the private sector, with important wellbeing consequences outside health and with heterogeneous welfare effects across socio-economic groups, other economic evaluation methods need to be developed in order to offer valid guidance to policy making. For these interventions, checklists for critical appraisal of economic evaluations may require some substantial changes., (Copyright © 2021. Published by Elsevier B.V.)
Published: 2021
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21. Discovery of relict subglacial lakes and their geometry and mechanism of drainage.

Author: Livingstone SJ, Utting DJ, Ruffell A, Clark CD, Pawley S, Atkinson N, and Fowler AC
Abstract: Recent proxy measurements reveal that subglacial lakes beneath modern ice sheets periodically store and release large volumes of water, providing an important but poorly understood influence on contemporary ice dynamics and mass balance. This is because direct observations of how lake drainage initiates and proceeds are lacking. Here we present physical evidence of the mechanism and geometry of lake drainage from the discovery of relict subglacial lakes formed during the last glaciation in Canada. These palaeo-subglacial lakes comprised shallow (<10 m) lenses of water perched behind ridges orientated transverse to ice flow. We show that lakes periodically drained through channels incised into bed substrate (canals). Canals sometimes trend into eskers that represent the depositional imprint of the last high-magnitude lake outburst. The subglacial lakes and channels are preserved on top of glacial lineations, indicating long-term re-organization of the subglacial drainage system and coupling to ice flow.
Published: 2016
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22. Commentary: the fading of the dream: widening inequalities in life expectancy in America.

Author: Dorling D
Subjects: Humans, Sex Factors, Socioeconomic Factors, United States, Life Expectancy trends
Published: 2006
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23. On the arid margin: the relationship between climate, humans and the environment. A review of evidence from the highlands of central Mexico.

Author: O'Hara SL, Metcalfe SE, and Street-Perrott FA
Subjects: Ecology, Geography, Humans, Mexico, Climate, Environment
Abstract: There has long been speculation as to the relationship between climate, humans and the environment. Until recently, however, it has proved difficult to establish the degree to which these factors are interlinked. Here we draw on evidence that has recently emerged from a series of investigations in central México to evaluate the long-term human impact on the environment and to establish the impact that late Holocene changes in the climate have had on the indigenous populations that lived on the arid frontier of Mesoamerica. Data from these studies indicate that: 1) the indigenous peoples of central México had a significant and often detrimental impact on the landscape, causing widespread land degradation; 2) The onset of anthropogenic accelerated erosion coincided with the introduction of sedentary agriculture in this region; 3) Fluctuations in the climate of central México over the last 4,000 years have had a significant impact on the subsistence strategies of the population which extended its territory into the northern arid lands during wetter periods, but rapidly abandoned these areas when the climate became drier.
Published: 1994
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23 results on '"Department of Geography [Sheffield]"'

1. Response to the discussion by Van Vliet-Lanoë et al. of the paper ‘Features caused by ground ice growth and decay in Late Pleistocene fluvial deposits, Paris Basin, France’ (Bertran et al., 2018, Geomorphology 310, 84–101)

2. Sinuous ridges in Chukhung crater, Tempe Terra, Mars: Implications for fluvial, glacial, and glaciofluvial activity

3. Mass balance of the ice sheets and glaciers – Progress since AR5 and challenges

4. Morphometry of a glacier-linked esker in NW Tempe Terra, Mars, and implications for sediment-discharge dynamics of subglacial drainage

5. The advance and retreat of the Irish Sea Ice Stream in the Celtic Sea and its influence on shelf evolution

6. Maximum extent and readvance dynamics of the Irish Sea Ice Stream since the Last Glacial Maximum

7. Mid-Devensian climate and landscape in England: new data from Finningley, South Yorkshire

8. Advance and retreat of the marine-terminating Irish Sea Ice Stream into the Celtic Sea during the Last Glacial: Timing and maximum extent

9. A stratigraphic investigation of the Celtic Sea megaridges based on seismic and core data from the Irish-UK sectors

10. Features caused by ground ice growth and decay in Late Pleistocene fluvial deposits, Paris Basin, France

11. The chronology of Late Pleistocene thermal contraction cracking derived from sand wedge OSL dating in central and southern France

12. The Greenland and Antarctic ice sheets under 1.5 °C global warming

13. Assessing recent trends in high-latitude Southern Hemisphere surface climate

14. Decadal slowdown of a land-terminating sector of the Greenland Ice Sheet despite warming

15. NEMO–ICB (v1.0): interactive icebergs in the NEMO ocean model globally configured at eddy-permitting resolution

16. Nitrate postdeposition processes in Svalbard surface snow

17. Nitrate dry deposition in Svalbard

18. Sustained monitoring of the Southern Ocean at Drake passage: past achievements and future priorities

19. Du bon usage de la pénurie en eau. Lorraine, 1949-1971

20. Economic evaluation of nutrition interventions: Does one size fit all?

21. Discovery of relict subglacial lakes and their geometry and mechanism of drainage.

22. Commentary: the fading of the dream: widening inequalities in life expectancy in America.

23. On the arid margin: the relationship between climate, humans and the environment. A review of evidence from the highlands of central Mexico.

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23 results on '"Department of Geography [Sheffield]"'

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