39 results on '"Fortier, Daniel"'
Search Results
2. Hydrological Regime and Plant Functional Traits Jointly Mediate the Influence of Salix spp. on Soil Organic Carbon Stocks in a High Arctic Tundra
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Lamarque, Laurent J., Félix-Faure, Jim, Deschamps, Lucas, Lévesque, Esther, Cusson, Pier-Olivier, Fortier, Daniel, Giacomazzo, Matteo, Guillemette, François, Paillassa, Jennifer, Tremblay, Maxime, and Maire, Vincent
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- 2023
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3. Cryostratigraphical studies of ground ice formation and distribution in a High Arctic polar desert landscape, Resolute Bay, Nunavut
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Paquette, Michel, Fortier, Daniel, and Lamoureux, Scott F.
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Resolute Bay, Canada -- Environmental aspects ,Geomorphological research ,Surface-ice melting -- Research ,Frozen ground -- Research ,Earth sciences - Abstract
Ground ice distribution and abundance have wide-ranging effects on periglacial environments and possible impacts on climate change scenarios. In contrast, very few studies measure ground ice in the High Arctic, especially in polar deserts and where coarse surficial material complicates coring operations. Ground ice volumes and cryostructures were determined for eight sites in a polar desert, near Resolute Bay, Nunavut, chosen for their hydrogeomorphic classification. Dry, unvegetated polar desert sites exhibited ice content close to soil porosity, with a Key words: ground ice, polar desert, permafrost, Arctic, geocryology, geomorphology. La répartition spatiale et l'abondance de la glace de sol ont d'importants effets sur les milieux périglaciaires et de possibles impacts sur les scénarios de changements climatiques. Très peu d'études mesurent cependant la glace de sol dans le Haut Arctique, en particulier dans les déserts polaires et là où des matériaux meubles grossiers rendent le carottage difficile. Les volumes et les cryostructures de la glace de sol ont été déterminés dans huit sites dans un désert polaire à proximité de Resolute Bay (Nunavut), sélectionnés selon leur classification hydrogéomorphologique. Les sites de désert polaire secs et exempts de végétation présentaient des teneurs en glace semblables aux valeurs de porosité du sol, ainsi qu'une zone de transition riche en glace de < 45 cm d'épaisseur. Dans les sites en milieu humide, des cryostructures suspendues et des cryofaciès dominés par la glace (de teneur en glace au moins deux fois plus grande que la porosité) prédominaient dans les deux premiers mètres du pergélisol. La saturation en glace moyenne du sol dans ces sites était de 1,8 à 20,1 fois plus grande que leur porosité, atteignant un facteur de plus de 2 ordres de grandeurs à une échelle verticale de ~10 cm. Les teneurs en glace les plus importantes ont été observées dans des sites qui étaient historiquement des milieux humides submergés caractérisés par un apport de sédiments, une disponibilité soutenue d'eau et un accroissement syngénétique et quasi-syngénétique du pergélisol. L'enrichissement qui se produisit surtout par aggradation de glace sous le front de dégel et par un engel vers le haut, causant du soulèvement gélival et formant des plateaus lithalsiques. La plupart des sites démontraient des indices cryostratigraphiques de dégradation de pergélisol. Dans le cas des milieux humides, cette dégradation est conséquentielle, car ces lieux sont des oasis opérant les fonctions essentielles d'écologie, d'hydrologie et des cycles des nutriments et contaminants. [Traduit par la Rédaction] Mots-clés : glace de sol, désert polaire, pergélisol, Arctique, géocryologie, géomorphologie., Introduction Ground ice formation and abundance is a foundational topic of geocryology. Among the focuses, knowing the spatial distribution of ground ice and identifying ice-rich areas is an important issue [...]
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- 2022
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4. Impacts of snow cover on the pattern and velocity of air flow in air convection embankments of sub-Arctic regions
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Chen, Lin, Lai, Yuanming, Fortier, Daniel, and Harris, Stuart A.
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- 2022
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5. Air-convection-reflective sheds: A mitigation technique that stopped degradation and promoted permafrost recovery under the Alaska Highway, south-western Yukon, Canada
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Gagnon, Samuel, Fortier, Daniel, Sliger, Michel, and Rioux, Karine
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- 2022
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6. Linking geomorphological processes and wildlife microhabitat selection: nesting birds select refuges generated by permafrost degradation in the Arctic.
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Corbeil-Robitaille, Madeleine-Zoé, Duchesne, Éliane, Fortier, Daniel, Kinnard, Christophe, and Bêty, Joël
- Abstract
To gain better insight into the cascading impact of warming-induced changes in the physical landscape on biodiversity, it is crucial to better understand links between abiotic and ecological processes governing species distribution. Abiotic processes shaping the physical characteristics of the environment could significantly influence predator movements in the landscape and ultimately affect biodiversity through interspecific interactions. In the Arctic tundra, the main terrestrial predator (Arctic fox) avoids patches of wetlands composed of ponds with islets that can act as refuges for prey. Little is known about the geomorphological processes generating islets selected by prey species. Our study aimed to identify (i) the physical characteristics of islets selected by Arctic-nesting birds and (ii) the geomorphological processes generating islets available in the landscape. Over two breeding seasons, we determined the occurrence of nesting birds (cackling goose, glaucous gull, and red-throated loon) on islets (N=396) found over a 165 km 2 area on Bylot Island (Nunavut, Canada). Occupied islets were located further away from the shore (10.6 m ± 7.3 SD vs. 7.4 m ± 6.8 SD) and surrounded by deeper water (33.6 cm ± 10.6 SD vs. 28.1 cm ± 11.5 SD) than unoccupied islets. As expected, all three bird species selected islets less accessible to Arctic foxes, with nesting occurrence increasing with distance to shore and water depth around islets. Based on high-resolution satellite imagery and field observations, we found that ice-wedge polygon degradation generated the majority of islets (71 %) found in the landscape. Those islets were on average farther from the shore and surrounded by deeper water than those generated by other processes. As polygon degradation is projected to accelerate in response to warming, new refuges will likely emerge in the Arctic landscape, but current refuges could also disappear. Changes in the rate of polygon degradation may thus affect Arctic tundra biodiversity by altering predator–prey interactions. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Supplementary material to "The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost"
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Gagnon, Samuel, primary, Fortier, Daniel, additional, Godin, Etienne, additional, and Veillette, Audrey, additional
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- 2024
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8. Pairing remote sensing and clustering in landscape hydrology for large-scale change identification: an application to the subarctic watershed of the George River (Nunavik, Canada)
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Sicaud, Eliot, primary, Fortier, Daniel, additional, Dedieu, Jean-Pierre, additional, and Franssen, Jan, additional
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- 2024
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9. Permafrost degradation and soil erosion as a driver of greenhouse gas emissions from tundra ponds
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Prėskienis, Vilmantas, primary, Fortier, Daniel, additional, Douglas, Peter, additional, Rautio, Milla, additional, and Laurion, Isabelle, additional
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- 2023
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10. Linking biodiversity and geodiversity: Arctic-nesting birds select refuges generated by permafrost degradation
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Corbeil-Robitaille, Madeleine-Zoé, primary, Duchesne, Éliane, additional, Fortier, Daniel, additional, Kinnard, Christophe, additional, and Bêty, Joël, additional
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- 2023
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11. The cryostratigraphy of thermo-erosion gullies in the Canadian High Arctic demonstrates the resilience of permafrost.
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Gagnon, Samuel, Fortier, Daniel, Godin, Etienne, and Veillette, Audrey
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PERMAFROST ,ICE ,TUNDRAS ,AGGRADATION & degradation ,LANDFORMS - Abstract
Thermo-erosion gullies (TEGs) are one of the most common forms of abrupt permafrost degradation. They generally form in ice-wedge polygonal networks where the interconnected troughs can channel runoff water. Although TEG can form within a single thawing season, it takes them several decades for their complete stabilization. While the inception of TEGs has been examined in several studies, the processes of their stabilization remain poorly documented, especially the ground ice patterns that form following permafrost aggradation in stabilizing TEGs. For this study, we investigated the impacts of two TEGs in the Canadian High Arctic (Bylot Island, NU, Canada) on ground ice content, cryostratigraphic patterns, and geomorphology to examine permafrost recovery following thermal erosion in ice-wedge polygonal tundra. We sampled 17 permafrost cores from two TEGs – one still active (since 1999) and one stabilized (>100 years old) – to describe the surface conditions, interpret the cryostratigraphic patterns, and characterize the state of permafrost after TEG stabilization. We observed that although the TEG caused discernable cryostratigraphic patterns, ground ice content and active layer thickness of the TEGs were comparable to measurements made in undisturbed conditions. We also noted that once stabilized, TEGs permanently (at the Anthropocene scale) alter landscape morphology and hydrological connectivity. We concluded that although the formation of a TEG has profound effects on the short/medium term and leaves near permanent geomorphological and hydrological scars in periglacial landscapes, on the long term, High Arctic permafrost can recover and return to geocryological conditions similar to those pre-dating the initial disturbance. This suggests that in stable environmental conditions undergoing natural variability, permafrost can persist longer than the geomorphological landforms in which it forms. [ABSTRACT FROM AUTHOR]
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- 2024
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12. State shifts and divergent sensitivities to climate warming across northern ecosystems
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Saulnier-Talbot, Émilie, primary, Duchesne, Eliane, additional, Antoniades, Dermot, additional, Arseneault, Dominique, additional, Barnard, Christine, additional, Berteaux, Dominique, additional, Bhiry, Najat, additional, Bouchard, Frédéric, additional, Boudreau, Stéphane, additional, Cazelles, Kevin, additional, Comte, Jérôme, additional, Corbeil-Robitaille, Madeleine-Zoé, additional, Côté, Steeve, additional, Couture, Raoul-Marie, additional, Fontaine, Guillaume de la, additional, Domine, Florent, additional, Fauteux, Dominique, additional, Fortier, Daniel, additional, Garneau, Michelle, additional, Gauthier, Gilles, additional, Gravel, Dominique, additional, Laurion, Isabelle, additional, Lavoie, Martin, additional, Lecomte, Nicolas, additional, Legagneux, Pierre, additional, Lévesque, Esther, additional, Naud, Marie-José, additional, Paquette, Michel, additional, Payette, Serge, additional, Pienitz, Reinhard, additional, Rautio, Milla, additional, Roy, Alexandre, additional, Royer, Alain, additional, Simard, Martin, additional, Vincent, Warwick, additional, and Bêty, Joël, additional
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- 2023
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13. Pairing remote sensing and clustering in landscape hydrology for large-scale changes identification. Applications to the subarctic watershed of the George River (Nunavik, Canada)
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Sicaud, Eliot, primary, Fortier, Daniel, additional, Dedieu, Jean-Pierre, additional, and Franssen, Jan, additional
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- 2023
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14. Subsurface Porewater Flow Accelerates Talik Development Under the Alaska Highway, Yukon: A Prelude to Road Collapse and Final Permafrost Thaw?
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Chen, Lin, primary, Fortier, Daniel, additional, McKenzie, Jeffrey M., additional, Voss, Clifford I., additional, and Lamontagne‐Hallé, Pierrick, additional
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- 2023
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15. Linking biodiversity and geodiversity: Arctic-nesting birds select refuges generated by permafrost degradation.
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Corbeil-Robitaille, Madeleine-Zoé, Duchesne, Éliane, Fortier, Daniel, Kinnard, Christophe, and Bêty, Joël
- Subjects
BIRD refuges ,TUNDRAS ,ARCTIC fox ,PERMAFROST ,PREDATION ,BIODIVERSITY ,GEODIVERSITY - Abstract
To gain better insight into the cascading impact of warming-induced changes in the physical landscape on biodiversity, it is crucial to establish stronger links between abiotic and ecological processes governing species distribution. Abiotic processes shaping the physical characteristics of the environment could significantly influence predator movements in the landscape and ultimately affect biodiversity through interspecific interactions. In the Arctic tundra, the main terrestrial predator (Arctic fox) avoids patches of wetlands composed of ponds with islets that can act as refuges for prey. Little is known about the geomorphological processes generating islets selected by prey species. Our study aimed to identify i) the physical characteristics of islets selected by Arctic-nesting birds and ii) the geomorphological processes generating islets available in the landscape. Over two breeding seasons, we determined the occurrence of nesting birds (Glaucous gull, Cackling goose, Red-throated loon) on islets (N=396) found over a 150 km
2 area on Bylot Island (Nunavut, Canada). Occupied islets were located further away from the shore (10.6 m ± 7.3 vs 7.4 m ± 6.8) and surrounded by deeper water (33.6 cm ± 10.6 vs 28.1 cm ± 11.5). As expected, all three bird species selected islets less accessible to Arctic foxes, with nesting occurrence increasing (linearly or nonlinearly) with distance to shore and/or water depth around islets. Based on high-resolution satellite image and field observations, we found that ice-wedge polygon degradation generated the majority of islets (71 %) found in the landscape. Those islets were on average farther from the shore and surrounded by deeper water than those generated by other processes. As polygon degradation is projected to accelerate in response to warming, new refuges will likely emerge in the Arctic landscape, but current refuges could also disappear. Changes in the rate of polygon degradation may thus affect Arctic tundra biodiversity by altering predator-prey interactions. [ABSTRACT FROM AUTHOR]- Published
- 2023
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16. Middle-Late Permian Dipnoi (Osteichthyes, Sarcopterygii) of Brazil, Comments on Their Ecological Interactions
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Figueiredo, Ana Emilia Quezado de, primary, Dentzien-Dias, Paula, additional, Cisneros, Juan C., additional, Fortier, Daniel Costa, additional, and Schultz, Cesar, additional
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- 2023
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17. Pairing remote sensing and clustering in landscape hydrology for large-scale changes identification. Applications to the subarctic watershed of the George River (Nunavik, Canada)
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Sicaud, Eliot, Fortier, Daniel, Dedieu, Jean-Pierre, Franssen, Jan, 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)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), and Université Grenoble Alpes (UGA)
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[SDE.IE]Environmental Sciences/Environmental Engineering ,[SDU.STU.HY]Sciences of the Universe [physics]/Earth Sciences/Hydrology ,[SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing - Abstract
For remote and vast northern watersheds, hydrological data are often sparse and incomplete. Landscape hydrology provides useful approaches for the indirect assessment of the hydrological characteristics of watersheds through analysis of landscape properties. In this study, we used unsupervised Geographic Object-Based Image Analysis (GeOBIA) paired with the Fuzzy C-Means (FCM) clustering algorithm to produce seven high-resolution territorial classifications of key remotely sensed hydro-geomorphic metrics for the 1985–2019 time-period, each spanning five years. Our study site is the George River watershed (GRW), a 42,000 km2 watershed located in Nunavik, northern Quebec (Canada). The subwatersheds within the GRW, used as the objects of the GeOBIA, were classified as a function of their hydrological similarities. Classification results for the period 2015–2019 showed that the GRW is composed of two main types of subwatersheds distributed along a latitudinal gradient, which indicates broad-scale differences in hydrological regimes and water balances across the GRW. Six classifications were computed for the period 1985–2014 to investigate past changes in hydrological regime. The seven-classification time series showed a homogenization of subwatershed types associated to increases in vegetation productivity and in water content in soil and vegetation, mostly concentrated in the northern half of the GRW, which were the major changes occurring in the land cover metrics of the GRW. An increase in vegetation productivity likely contributed to an augmentation in evapotranspiration and may be a primary driver of fundamental shifts in the GRW water balance, potentially explaining a measured decline of about 1 % (∼ 0.16 km3 y−1) in the George River’s discharge since the mid-1970s. Permafrost degradation over the study period also likely affected the hydrological regime and water balance of the GRW. However, the shifts in permafrost extent and active layer thickness remain difficult to detect using remote sensing based approaches, particularly in areas of discontinuous and sporadic permafrost.
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- 2023
18. Increased nutrient availability speeds up permafrost development, while goose grazing slows it down in a Canadian High Arctic wetland
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Deschamps, Lucas, primary, Maire, Vincent, additional, Chen, Lin, additional, Fortier, Daniel, additional, Gauthier, Gilles, additional, Morneault, Amélie, additional, Hardy‐Lachance, Elisabeth, additional, Dalcher‐Gosselin, Isabelle, additional, Tanguay, François, additional, Gignac, Charles, additional, McKenzie, Jeffrey M., additional, Rochefort, Line, additional, and Lévesque, Esther, additional
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- 2022
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19. Contrasted geomorphological and limnological properties of thermokarst lakes formed in buried glacier ice and ice-wedge polygon terrain
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Coulombe, Stéphanie, primary, Fortier, Daniel, additional, Bouchard, Frédéric, additional, Paquette, Michel, additional, Charbonneau, Simon, additional, Lacelle, Denis, additional, Laurion, Isabelle, additional, and Pienitz, Reinhard, additional
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- 2022
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20. Yedoma permafrost genesis: Over 150 years of mystery and controversy
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Shur, Yuri, Fortier, Daniel, Jorgenson, Torre, Kanevskiy, Mikhail, Schirrmeister, Lutz, Strauss, Jens, Vasiliev, Alexander A., Ward Jones, Melissa, Shur, Yuri, Fortier, Daniel, Jorgenson, Torre, Kanevskiy, Mikhail, Schirrmeister, Lutz, Strauss, Jens, Vasiliev, Alexander A., and Ward Jones, Melissa
- Abstract
Since the discovery of frozen megafauna carcasses in Northern Siberia and Alaska in the early 1800s, the Yedoma phenomenon has attracted many Arctic explorers and scientists. Exposed along coastal and riverbank bluffs, Yedoma often appears as large masses of ice with some inclusions of sediment. The ground ice particularly mystified geologists and geographers, and they considered sediment within Yedoma exposures to be a secondary and unimportant component. Numerous scientists around the world tried to explain the origin of Yedoma for decades, even though some of them had never seen Yedoma in the field. The origin of massive ice in Yedoma has been attributed to buried surface ice (glaciers, snow, lake ice, and icings), intrusive ice (open system pingo), and finally to ice wedges. Proponents of the last hypothesis found it difficult to explain a vertical extent of ice wedges, which in some cases exceeds 40 m. It took over 150 years of intense debates to understand the process of ice-wedge formation occurring simultaneously (syngenetically) with soil deposition and permafrost aggregation. This understanding was based on observations of the contemporary formation of syngenetic permafrost with ice wedges on the floodplains of Arctic rivers. It initially was concluded that Yedoma was a floodplain deposit, and it took several decades of debates to understand that Yedoma is of polygenetic origin. In this paper, we discuss the history of Yedoma studies from the early 19th century until the 1980s—the period when the main hypotheses of Yedoma origin were debated and developed.
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- 2022
21. Landscape-related ground ice variability on the Yukon coastal plain inferred from computed tomography and remote sensing
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Pika, Philip, Tanski, George, Ulrich, Mathias, Roy, Louis-Philippe, Calmels, Fabrice, Lantuit, Hugues, Fortier, Daniel, Fritz, Michael, Vonk, Jorien E., Pika, Philip, Tanski, George, Ulrich, Mathias, Roy, Louis-Philippe, Calmels, Fabrice, Lantuit, Hugues, Fortier, Daniel, Fritz, Michael, and Vonk, Jorien E.
- Abstract
Warming in the Arctic causes strong environmental changes with degradation of permafrost (permanently frozen ground). Active layer deepening (gradual thaw) and permafrost erosion (abrupt thaw) results in the mobilization and lateral transport of organic carbon, altering current carbon cycling in the Arctic. Ground ice content is a crucial factor limiting our understanding and ability to determine the rates and dynamics of permafrost thaw and its impact on potential thaw subsidence rates, changes in lateral hydrological pathways and its driving mechanisms on a landscape scale. In this study we investigate ground ice content and its characteristics across the most dominant landscape units of the Yukon coastal plain (Canadian Arctic), using two spatially and technically contrasting approaches. In our bottom-up approach, twelve permafrost cores were collected from moraine, lacustrine, fluvial and glaciofluvial deposits using a SIPRE corer (mean drilling depth of 2 m) in spring of 2019. Ground ice and sediment contents within polygon centers were analyzed and classified using computed tomography and image recognition software (k-means). Our top-down approach quantified ice-wedge volumes from remote sensing imagery tracing the circumference of polygon troughs over the same area. Preliminary results - extrapolated to the entire coastal plain - show that the ground-ice content in polygon centers vary significantly from massive ice in the polygon troughs (wedge-ice). Total ice volume was estimated around 80.2 vol.-%, of which 68.2 ± 18.1 vol.-% was attributed to ground ice in polygon centers, and 12 ± 3.1 vol.-% of the landscape is massive ice in wedge-ice along polygon troughs. Additionally, differences among and between landscape units are also substantial, with highest ice volume contents in moraines landscapes, where polygon centers contain 58.8 vol.-% ground ice and wedge-ice volume is 16.2 vol.-%), while the lowest ice contents are found in glacio-fluvial deposits (22.
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- 2022
22. Rock wall freeze-thaw dynamic in a climate change context
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Birien, Tom, primary, Gauthier, Francis, additional, and Fortier, Daniel, additional
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- 2022
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23. Properties and stratigraphy of polar ice patches in the Canadian High Arctic reveal their current resilience to warm summers
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Davesne, Gautier, primary, Fortier, Daniel, additional, and Domine, Florent, additional
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- 2022
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24. Yedoma Cryostratigraphy of Recently Excavated Sections of the CRREL Permafrost Tunnel Near Fairbanks, Alaska
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Kanevskiy, Mikhail, Shur, Yuri, Bigelow, Nancy H., Bjella, Kevin L., Douglas, Thomas A., Fortier, Daniel, Jones, Benjamin M., and Jorgenson, M. Torre
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General Earth and Planetary Sciences - Abstract
Recent excavation in the new CRREL Permafrost Tunnel in Fox, Alaska provides a unique opportunity to study properties of Yedoma — late Pleistocene ice- and organic-rich syngenetic permafrost. Yedoma has been described at numerous sites across Interior Alaska, mainly within the Yukon-Tanana upland. The most comprehensive data on the structure and properties of Yedoma in this area have been obtained in the CRREL Permafrost Tunnel near Fairbanks — one of the most accessible large-scale exposures of Yedoma permafrost on Earth, which became available to researchers in the mid-1960s. Expansion of the new ∼4-m-high and ∼4-m-wide linear excavations, started in 2011 and ongoing, exposes an additional 300 m of well-preserved Yedoma and provides access to sediments deposited over the past 40,000 years, which will allow us to quantify rates and patterns of formation of syngenetic permafrost, depositional history and biogeochemical characteristics of Yedoma, and its response to a warmer climate. In this paper, we present results of detailed cryostratigraphic studies in the Tunnel and adjacent area. Data from our study include ground-ice content, the stable water isotope composition of the variety of ground-ice bodies, and radiocarbon age dates. Based on cryostratigraphic mapping of the Tunnel and results of drilling above and inside the Tunnel, six main cryostratigraphic units have been distinguished: 1) active layer; 2) modern intermediate layer (ice-rich silt); 3) relatively ice-poor Yedoma silt reworked by thermal erosion and thermokarst during the Holocene; 4) ice-rich late Pleistocene Yedoma silt with large ice wedges; 5) relatively ice-poor fluvial gravel; and 6) ice-poor bedrock. Our studies reveal significant differences in cryostratigraphy of the new and old CRREL Permafrost Tunnel facilities. Original syngenetic permafrost in the new Tunnel has been better preserved and less affected by erosional events during the period of Yedoma formation, although numerous features (e.g., bodies of thermokarst-cave ice, thaw unconformities, buried gullies) indicate the original Yedoma silt in the recently excavated sections was also reworked to some extent by thermokarst and thermal erosion during the late Pleistocene and Holocene.
- Published
- 2022
25. Increased nutrient availability speeds up permafrost development, while goose grazing slows it down in a Canadian High Arctic wetland.
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Deschamps, Lucas, Maire, Vincent, Chen, Lin, Fortier, Daniel, Gauthier, Gilles, Morneault, Amélie, Hardy‐Lachance, Elisabeth, Dalcher‐Gosselin, Isabelle, Tanguay, François, Gignac, Charles, McKenzie, Jeffrey M., Rochefort, Line, and Lévesque, Esther
- Subjects
TUNDRAS ,PERMAFROST ,ENERGY budget (Geophysics) ,GRAZING ,LEAF area index ,GEESE - Abstract
Copyright of Journal of Ecology is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2023
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26. Landscape-related ground ice variability on the Yukon coastal plain inferred from computed tomography and remote sensing
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Pika, Philip, primary, Tanski, George, additional, Ulrich, Mathias, additional, Roy, Louis-Philippe, additional, Calmels, Fabrice, additional, Lantuit, Hugues, additional, Fortier, Daniel, additional, Fritz, Michael, additional, and Vonk, Jorien, additional
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- 2022
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27. Remote Sensing and Clustering Applications in Landscape Hydrology: Characterizing a Subarctic Watershed in Nunavik (Canada)
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Sicaud, Eliot, primary, Franssen, Jan, additional, Dedieu, Jean-Pierre, additional, and Fortier, Daniel, additional
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- 2022
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28. Yedoma Permafrost Genesis: Over 150 Years of Mystery and Controversy
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Shur, Yuri, primary, Fortier, Daniel, additional, Jorgenson, M. Torre, additional, Kanevskiy, Mikhail, additional, Schirrmeister, Lutz, additional, Strauss, Jens, additional, Vasiliev, Alexander, additional, and Ward Jones, Melissa, additional
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- 2022
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29. Supplementary material to "Thermokarst lakes formed in buried glacier ice: Observations from Bylot Island, eastern Canadian Arctic"
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Coulombe, Stéphanie, primary, Fortier, Daniel, additional, Bouchard, Frédéric, additional, Paquette, Michel, additional, Lacelle, Denis, additional, and Laurion, Isabelle, additional
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- 2021
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30. Thermokarst lakes formed in buried glacier ice: Observations from Bylot Island, eastern Canadian Arctic
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Coulombe, Stéphanie, primary, Fortier, Daniel, additional, Bouchard, Frédéric, additional, Paquette, Michel, additional, Lacelle, Denis, additional, and Laurion, Isabelle, additional
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- 2021
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31. Circum-Arctic Map of the Yedoma Permafrost Domain
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Strauss, Jens, primary, Laboor, Sebastian, additional, Schirrmeister, Lutz, additional, Fedorov, Alexander N., additional, Fortier, Daniel, additional, Froese, Duane, additional, Fuchs, Matthias, additional, Günther, Frank, additional, Grigoriev, Mikhail, additional, Harden, Jennifer, additional, Hugelius, Gustaf, additional, Jongejans, Loeka L., additional, Kanevskiy, Mikhail, additional, Kholodov, Alexander, additional, Kunitsky, Viktor, additional, Kraev, Gleb, additional, Lozhkin, Anatoly, additional, Rivkina, Elizaveta, additional, Shur, Yuri, additional, Siegert, Christine, additional, Spektor, Valentin, additional, Streletskaya, Irina, additional, Ulrich, Mathias, additional, Vartanyan, Sergey, additional, Veremeeva, Alexandra, additional, Anthony, Katey Walter, additional, Wetterich, Sebastian, additional, Zimov, Nikita, additional, and Grosse, Guido, additional
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- 2021
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32. Cryostratigraphical studies of ground ice formation and distribution in a High Arctic polar desert landscape, Resolute Bay, Nunavut1.
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Paquette, Michel, Fortier, Daniel, and Lamoureux, Scott F.
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ICE , *WATER supply , *WETLANDS , *SOIL porosity , *FROST heaving , *DESERTS - Abstract
Ground ice distribution and abundance have wide-ranging effects on periglacial environments and possible impacts on climate change scenarios. In contrast, very few studies measure ground ice in the High Arctic, especially in polar deserts and where coarse surficial material complicates coring operations. Ground ice volumes and cryostructures were determined for eight sites in a polar desert, near Resolute Bay, Nunavut, chosen for their hydrogeomorphic classification. Dry, unvegetated polar desert sites exhibited ice content close to soil porosity, with a <45 cm thick ice-enriched transition zone. In wetland sites, suspended cryostructures and ice dominated cryofacies (ice content at least 2× soil porosity values) were prevalent in the upper ∼2 m of permafrost. Average ground ice saturation at those locations exceeded porosity values by a factor between 1.8 and 20.1 and by up to two orders of magnitude at the ∼10 cm vertical scale. Sites with the highest ice contents were historically submerged wetlands with a history of sediment supply, sustained water availability, and syngenetic and quasi-syngenetic permafrost aggradation. Ice enrichment in those environments were mainly caused by the strong upward freezing potential beneath the thaw front, which, combined with abundant water supply, caused ice aggradation and frost heaving to form lithalsa plateaus. Most of the sites already expressed cryostratigraphic evidence of permafrost degradation. Permafrost degradation carries important ecological ramifications, as wetland locations are the most productive, life-supporting oases in the otherwise relatively barren landscape, carrying essential functions linked with hydrological processes and nutrient and contaminant cycling. [ABSTRACT FROM AUTHOR]
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- 2022
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33. Cryostratigraphical studies of ground ice formation and distribution in a High Arctic polar desert landscape, Resolute Bay, Nunavut1.
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Paquette, Michel, Fortier, Daniel, and Lamoureux, Scott F.
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ICE ,WATER supply ,WETLANDS ,SOIL porosity ,FROST heaving ,DESERTS - Abstract
Copyright of Canadian Journal of Earth Sciences is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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- 2022
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34. Effects of meteorology and soil moisture on the spatio-temporal evolution of the depth hoar layer in the polar desert snowpack
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Davesne, Gautier, primary, Domine, Florent, additional, and Fortier, Daniel, additional
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- 2021
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35. Effects of meteorology and soil moisture on the spatio-temporal evolution of the depth hoar layer in the polar desert snowpack.
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Davesne, Gautier, Domine, Florent, and Fortier, Daniel
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SOIL moisture ,SPATIOTEMPORAL processes ,DESERTS ,METEOROLOGY ,TRAFFIC safety ,SNOW accumulation - Abstract
In polar deserts, depth hoar (hereinafter: DH) growth is not systematic unlike on tundra and this is critical for snowpack properties. Here, we address the spatio-temporal variability of the DH layer in the polar desert at two sites in the Canadian High Arctic: Ward Hunt Island (83° N) and Resolute Bay (75° N). Our data show that, over humid areas, DH represented a larger fraction of the snowpack and was characterized by lower density and coarser crystals than over dry gravelly areas. Increased soil moisture extends the zero-curtain period during freeze-up, leading to stronger temperature gradients in the snowpack and greater kinetic metamorphism. Our results also demonstrate that the large inter-annual variability in DH is primarily driven by wind conditions in the fall since this key variable controls the initial snow density and snow onset date. These strong controls exerted by soil moisture and meteorological conditions on DH growth in polar deserts highlight the possibility of major changes in polar snowpacks physical properties in response to the rapid climate and environmental changes currently affecting these regions. [ABSTRACT FROM AUTHOR]
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- 2022
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36. Surface energy balance of sub‐Arctic roads with varying snow regimes and properties in permafrost regions.
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Chen, Lin, Voss, Clifford I., Fortier, Daniel, and McKenzie, Jeffrey M.
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ALASKA Highway ,SURFACE energy ,PERMAFROST ,SNOW cover ,EARTH temperature ,SNOW removal ,EMBANKMENTS ,SNOW accumulation - Abstract
Surface energy balance (SEB) strongly influences the thermal state of permafrost, cryohydrological processes, and infrastructure stability. Road construction and snow accumulation affect the energy balance of underlying permafrost. Herein, we use an experimental road section of the Alaska Highway to develop a SEB model to quantify the surface energy components and ground surface temperature (GST) for different land cover types with varying snow regimes and properties. Simulated and measured ground temperatures are in good agreement, and our results show that the quantity of heat entering the embankment center and slope is mainly controlled by net radiation, and less by the sensible heat flux. In spring, lateral heat flux from the embankment center leads to earlier disappearance of snowpack on the embankment slope. In winter, the insulation created by the snow cover on the embankment slope reduces heat loss by a factor of three compared with the embankment center where the snow is plowed. The surface temperature offsets are 5.0°C and 7.8°C for the embankment center and slope, respectively. Furthermore, the heat flux released on the embankment slope exponentially decreases with increasing snow depth, and linearly decreases with earlier snow cover in fall and shorter snow‐covered period in spring. [ABSTRACT FROM AUTHOR]
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- 2021
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37. La glace de glacier enfouie dans le pergélisol de l’île Bylot : origine, caractéristiques et impacts géomorphologiques
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Coulombe, Stéphanie and Fortier, Daniel
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Paleomagnetism ,Arctique canadien ,Cryostratigraphie ,Géochimie ,Permafrost ,Pergélisol ,Thermokarst ,Paléomagnétisme ,Glacier ice ,Geochemistry ,Pléistocène ,Glaciations ,Glace de glacier ,Canadian Arctic - Abstract
Au cours des dernières décennies, les observations de glace de glacier enfouie exposée dans les falaises côtières et les glissements de terrain causés par le dégel du pergélisol arctique démontrent que des quantités importantes de glace de glacier ont survécu à la déglaciation et sont toujours préservées dans le pergélisol. Le premier volet de cette étude visait à caractériser des expositions de la glace massive observée à l’île Bylot, au Nunavut, afin de connaitre l’origine de la glace. Puisque la glace de glacier enfouie peut jouer un rôle important dans l’évolution des paysages périglaciaires, cette thèse s’intéresse également au rôle joué par la glace de glacier enfouie dans l'initiation et l’évolution de lacs de thermokarst. Nos résultats démontrent que le pergélisol de l'île Bylot contient des restes de glace de glacier du Pléistocène qui ont survécu aux dernières déglaciations. Dans la vallée Qarlikturvik, des masses de glace intraglaciaire (dérivée du névé) sont associées à un courant de glace de l’inlandsis laurentidien qui recouvrait une partie de la plaine sud de l’île vers la fin du Pléistocène. Cette masse de glace formait une zone de convergence avec les glaciers alpins locaux s'écoulant de la calotte glaciaire centrée sur les monts Byam Martin. Sur l’un des plateaux bordant la vallée Qarlikturvik, une masse de glace de glacier enfouie est associée à la partie basale d'un glacier dont l’âge minimal est estimé à environ 0.77 Ma, mais pourrait être aussi vieux que 2.6 Ma. En raison de sa localisation, à environ 500 m d’altitude, la glace proviendrait vraisemblablement d’une avancée glaciaire régionale et pourrait être associée à la Glaciation de Baffin, soit la plus vieille avancée glaciaire régionale reconnue sur l'île Bylot. De plus, cette glace représente le plus vieux reste de glacier connu en Amérique du Nord et l’une des premières indications de glaciations dans l’est de l’Arctique canadien. La persistance et la fonte tardive de ces épaisses couches de glace de glacier datant du Pléistocène ont eu des effets importants sur le paysage de l'île Bylot, notamment sur les lacs. En effet, nos résultats démontrent que l'initiation des lacs profonds (> 5 m) est liée à la fonte de la glace de glacier enfouie. Ces lacs de thermokarst glaciaire continueront d’évoluer dans un contexte périglaciaire par la fonte de la glace intrasédimentaire (p. ex., glace de ségrégation) et des coins de glace formés ultérieurement dans les sédiments encaissants lors de l’aggradation du pergélisol suivant le retrait glaciaire. Alors qu’une grande partie des paysages arctiques est encore fortement déterminée par leur héritage glaciaire, la fonte de ces masses de glace aura un impact important sur la dynamique des géosystèmes et écosystèmes arctiques., Over the past decades, observations of buried glacier ice exposed in coastal bluffs and headwalls of retrogressive thaw slumps of the Arctic have indicated that considerable amounts of late Pleistocene glacier ice survived the deglaciation and are still preserved in permafrost. The first phase of this project aimed to characterize two exposures of massive ice observed on Bylot Island (Nunavut) to infer their origins. Since buried glacier ice can play a significant role in reshaping periglacial landscapes, this study also investigates the initiation and development of thermokarst lakes in a tundra valley in response to the melting of buried glacier ice. Our results show that the permafrost of Bylot Island contains remnants of Pleistocene glacier ice that survived the past deglaciations. In the Qarlikturvik valley, bodies of englacial ice (firn-derived) originated from an ice stream flowing from the Laurentide Ice Sheet, which covered part of the southern plain of the island towards the end of the Pleistocene. These glacier ice bodies formed a convergence zone with local alpine glaciers flowing from the ice cap centred over the Byam Martin Mountains. On the edge of a flat plateau bordering the Qarlikturvik Valley, a buried glacier ice body is associated with the basal part of a glacier whose minimum age is estimated at 0.77 Ma, but could be as old as 2.6 Ma. Due to its location on a 500-m a.s.l. plateau, the ice likely originates from a regional glacial advance and could be associated with the Baffin Glaciation, which is the oldest known glaciation on Bylot Island. In addition, this buried glacier ice represents the oldest glacier ice preserved in ice-free Arctic landscapes, and the earliest evidence of a Pleistocene glaciation in the eastern Canadian Arctic Archipelago. The persistence and delayed melting of these thick beds of buried Pleistocene glacier ice had wide-ranging effects on the landscape of Bylot Island. Our results suggest that the initiation of deeper thermokarst lakes (> 5 m) was triggered by the melting of buried glacier ice in our study area, while shallow thermokarst lakes were triggered from the melting of intrasedimental ice and ice wedges. These glacial thermokarst lakes will continue to evolve in a periglacial context through the melting of intrasedimental ice (e.g. segregation ice) and ice wedges subsequently formed in the surrounding sediments during permafrost aggradation following the glacial retreat. As most of the glaciated Arctic landscapes are still strongly determined by their glacial legacy, the melting of these large ice bodies will have significant impacts on Arctic ecosystems and geosystems.
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- 2023
38. Caractérisation hydrogéomorphométrique du bassin versant de la Rivière George (Nunavik) par télédétection et analyse typologique
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Sicaud, Eliot and Fortier, Daniel
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remote sensing ,bassin versant subarctique ,hydrologie paysagère ,télédétection ,analyse typologique ,Arctic greening ,landscape hydrology ,Subarctic watershed ,enverdissement ,clustering - Abstract
Ce mémoire a pour objectif d’approfondir les connaissances scientifiques sur les comportements hydrologiques des bassins versants arctiques et subarctiques. Les rivières drainant ces bassins versants sont parmi les systèmes fluviaux les moins étudiés et compris, étant donné leur vaste étendue et leur localisation éloignée. L’approche utilisée, issue de la discipline de l’hydrologie paysagère, présente une technique de classifications non-supervisées jumelées à des données de télédétection afin de caractériser le comportement hydrologique et les changements à l’échelle du paysage qui se sont produits sur les 35 dernières années dans un bassin versant subarctique de 42 000 km2. Plus précisément, plusieurs analyses géographiques d’image orientées-objet (AGIOO), employant des variables hydrogéomorphométriques et combinées à l’algorithme de classification Fuzzy C-Means, ont été produites, puis comparées afin de classifier et identifier les changements dans le paysage du vaste bassin versant de la Rivière George (BVRG), situé au Nunavik (Canada). Nos résultats indiquent que le BVRG contient deux types distincts de sous-bassins versants typologiquement similaires, distribués selon un gradient latitudinal, mettant en lumière une hétérogénéité spatiale dans les structures des sous-bassins constituant le BVRG. De plus, une expansion du type de bassins versants du sud dans le nord du BVRG est observée depuis les 35 dernières années. Cette expansion est principalement due à une augmentation de la production végétale et de l’humidité contenue dans les sols et la végétation, elle-même induite par une augmentation des températures moyennes annuelles et des précipitations totales annuelles associée aux changements climatiques. Ces changements observés dans la couverture terrestre ont des impacts importants et à long terme sur les processus hydrologiques du BVRG en augmentant les taux d’évapotranspiration. Ce phénomène pourrait expliquer la diminution d’environ 1% des débits annuels observée dans le BVRG entre les années 1970 et 2017., The objective of this study is to develop scientific knowledge on the hydrological behaviors of Arctic and Subarctic watersheds. Rivers draining high-latitude watersheds are among the least studied and understood fluvial systems, given their large extent and their remote locations. Here we develop a landscape hydrology approach which pairs unsupervised classifications with remote sensing data to characterize the hydrological behavior and landscape scale changes that have occurred over a 42 000 km2 sub-arctic watershed over the last 35 years. More precisely, multiple Geographic Object-Based Image Analysis (GeOBIA), employing hydrogeomorphometric variables and combined to the Fuzzy C-Means clustering algorithm, were produced and then compared to classify and identify landscape change across the vast George River Watershed (GRW), situated in Nunavik (Canada). Our results indicate that the GRW contains two distinct subwatershed types which are distinct in their typology and distributed along a latitudinal gradient, which highlights spatial heterogeneity in the structures of the subwatersheds constituting the GRW. Moreover, an expansion of the southern type subwatersheds in the north of the GRW has been observed since the last 35 years. This expansion is principally due to increases in vegetation production and moisture content in soils and vegetation, themselves induced by increases in mean annual temperature (MAT) and total annual precipitation (TAP) associated with the changing climate in this northern watershed. These land cover changes are likely to have important and long-term impacts on the hydrological processes within the GRW by increasing rates of evapotranspiration. This phenomenon may explain the decrease of about 1% in the George River’s annual discharge observed between the mid-1970s and 2017.
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- 2022
39. Plaques de glace permanentes : étude de leurs caractéristiques intrinsèques et de leurs effets sur la dynamique hydrologique et biogéomorphologique des versants du désert polaire arctique
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Davesne, Gautier and Fortier, Daniel
- Subjects
Polar desert ,Solifluction ,Ward Hunt Island ,Solifluxion ,Nivation ,Plaque de glace ,Ile Ward Hunt ,Désert polaire ,Neige ,Snow ,Évolution des versants ,Cryosphère ,Hydrology ,Slope evolution ,Cryosphere ,Hydrologie ,Ice patch - Abstract
Les plaques de glace forment de petites masses de glace et de neige permanentes qui sont considérées comme un stade intermédiaire dans le continuum neige-glacier. Elles sont omniprésentes dans les régions polaires, ce qui leur confère une fonction centrale dans l’hydrologie et la géomorphologie des versants. Pourtant, très peu d’études s’y sont intéressées jusqu’à présent. Acquérir des connaissances sur ces plaques apparait donc essentiel, non seulement pour comprendre leurs caractéristiques intrinsèques, mais aussi parce que cela ouvre des perspectives importantes pour comprendre la dynamique du géosystème polaire. Afin de répondre à ce besoin, cette thèse cherche à établir l'origine et le fonctionnement des plaques de glace à l’île Ward Hunt (Haut-Arctique canadien) et d’en comprendre les effets sur la dynamique de versant du désert polaire. Cette recherche sur les plaques de glace a été guidée par une approche multidisciplinaire, conduisant à des études glaciologiques, nivologiques, hydrologiques et biogéomorphologiques. Nos résultats ont montré que les plaques de glace se développent par l’aggradation de glace surimposée qui se forme suite au regel de l'eau de fonte à la base de l’accumulation de neige saisonnière. La texture et les propriétés physiques de cette glace varient en fonction de son âge et de l’intensité des processus de recristallisation. La variabilité spatio-temporelle des plaques de glace est principalement contrôlée par la topographie locale et les conditions micrométéorologiques. En hiver, les apports en neige dans les niches topographiques où se forment les plaques de glace sont assurés par le vent. En été, l’intensité de l’ablation est fortement influencée par le vent et le brouillard, qui modulent les échanges d’énergie à la surface des plaques. L'évolution des plaques de glace se caractérise par une stabilité à long terme due à un mécanisme d'autorégulation du bilan de masse assuré par le contexte topoclimatique. Cependant, en raison de leur petite taille, les plaques de glace peuvent disparaître rapidement lorsque l'ablation estivale dépasse un seuil à partir duquel les conditions topoclimatiques ne peuvent plus assurer leur préservation. À Ward Hunt, la présence des plaques de glace depuis au moins plusieurs siècles fait qu’elles ont fortement contribué au développement des versants. Les apports durables en eau et sédiments qui en découlent en été ont enclenché une suite de processus abiotiques et biotiques azonaux dans les marges pronivales. Il en a résulté la formation de systèmes biogéomorphologiques qui consistent en des lobes de solifluxion et des milieux humides colonisés par de la végétation et un couvert de croute biologique. Les modifications morphologiques et physiques du sol en aval des plaques de glace influencent le régime thermique de surface et les profondeurs de dégel. En outre, le développement des zones humides entraine une modification locale des propriétés physiques de la neige en exacerbant le métamorphisme cinétique qui aboutit à la croissance d’une couche de givre de profondeur à la base du manteau neigeux. En apportant une compréhension holistique des plaques de glace polaires, cette thèse permet des avancées empiriques et conceptuelles importantes qui contribuent à mieux comprendre la dynamique du géosystème de désert polaire à un moment charnière où ces environnements subissent en transition rapide en réponse au changement climatique., Ice patches are small perennial masses of ice and snow that are considered as part of the continuum between seasonal snow and glacier. They are ubiquitous in the Polar Regions, which gives them an important function in slope hydrology and geomorphology. Ice patches have, however, received very little scientific attention so far. Gaining new knowledge on these cryospheric elements thus appears essential, not only to understand their intrinsic characteristics, but also because it holds important perspectives for understanding the dynamics of the polar geosystem. To address this need, this thesis aims to investigate the origin and functioning of the ice patches at Ward Hunt Island (Canadian High Arctic) and to understand their effects on polar desert slope dynamics. This research on ice patches was guided by a multidisciplinary approach, involving glaciological, snow, hydrological and biogeomorphological studies. Our results demonstrated that ice patches develop through the aggradation of superimposed ice that forms by the refreezing of meltwater at the base of the seasonal snowpack. The texture and physical properties of this ice vary according to its age and the intensity of recrystallization processes. The spatio-temporal variability of ice patches is mainly controlled by local topography and micrometeorological conditions. In winter, the snow supply to the topographic niches where ice patches form is provided by the wind. In summer, the intensity of ablation is strongly influenced by wind and fog, which modulate energy exchange at the surface of the patches. The evolution of ice patches is characterized by long-term stability due to a self-regulating mass balance mechanism provided by the topoclimatic context. However, because of their small size, ice patches can disappear very quickly when summer ablation exceeds a threshold at which topoclimatic conditions can no longer ensure their preservation. At Ward Hunt Island, the presence of the ice patches for at least several centuries makes them important drivers of slope development. Sustained meltwater and sediment supplies delivered by ice patches to their pronival margin have triggered a sequence of abiotic and biotic azonal processes. This led to the formation of a biogeomorphic system, consisting of solifluction lobes and humid zones colonized by vegetation and an organic crust cover. Morphological and physical changes in the soil downslope of the ice patches influenced the surface thermal regime and thaw depths. Furthermore, our results show that the humid zone development leads to a local modification of the physical properties of snow by enhancing kinetic metamorphism responsible for the growth of a depth hoar layer at the base of the snowpack. Through a comprehensive understanding of polar ice patches and their effects, this thesis provides important empirical and conceptual advances that contribute to a better understanding of polar desert geosystem dynamics at a pivotal time when these environments are undergoing a rapid transition in response to climate change.
- Published
- 2022
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