GEOSCAN, résultats de la recherche

Menu GEOSCAN


Titre20 Years of active layer monitoring in the Mackenzie Valley, Northwest Territories
TéléchargerTéléchargements
AuteurDuchesne, C; Smith, S L; Ednie, M; Chartrand, J
SourceCommission géologique du Canada, Présentation scientifique 31, 2015, 2 pages (1 feuille), https://doi.org/10.4095/296513
Image
Année2015
ÉditeurRessources naturelles Canada
RéunionArctic Change 2014; Ottawa; CA; décembre 8-12, 2014
Documentpublication en série
Lang.anglais
DOIhttps://doi.org/10.4095/296513
Mediaen ligne; numérique
Référence reliéeCette publication est reliée Duchesne, C; Smith, S L; Ednie, M; Chartrand, J; (2014). 20 Years of active layer monitoring in the Mackenzie Valley, Northwest Territories, Arctic Change 2014, poster abstracts
Formatspdf
ProvinceTerritoires du Nord-Ouest; Alberta
SNRC84J/03; 84J/04; 84J/05; 84J/06; 84J/11; 84J/12; 84J/13; 84J/14; 84K; 84L; 84M; 84N; 84O/03; 84O/04; 84O/05; 84O/06; 84O/11; 84O/12; 84O/13; 84O/14; 85B/03; 85B/04; 85B/05; 85B/06; 85B/11; 85B/12; 85B/13; 85B/14; 85C; 85D; 85E; 85F; 85K/02; 85K/03; 85K/04; 85K/05; 85K/06; 85K/11; 85K/12; 85K/13; 85L; 85M/01; 85M/02; 85M/03; 85M/04; 85M/05; 85M/06; 85M/07; 85M/11; 85M/12; 85M/13; 95A; 95B; 95E; 95F; 95G; 95H; 95I; 95J; 95K; 95M; 95N; 95O; 95P; 96A; 96B; 96C; 96D; 96E; 96F; 96G; 96K; 96L; 96M/01; 96M/02; 96M/03; 96M/04; 96M/05; 96M/06; 96M/07; 96M/12; 106A; 106G/01; 106G/07; 106G/08; 106G/09; 106G/10; 106G/14; 106G/15; 106G/16; 106H; 106I; 106J; 106K/08; 106K/09; 106K/10; 106K/14; 106K/15; 106K/16; 106M; 106N; 106O; 106P; 107A/02; 107A/03; 107A/04; 107A/05; 107A/06; 107A/11; 107A/12; 107A/13; 107B; 107C/01; 107C/02; 107C/03; 107C/04; 107C/05; 107C/06; 107C/07; 107C/08; 107C/10; 107C/11; 107C/12; 107C/13; 107C/14; 116P/01; 116P/08; 116P/09; 116P/16; 117A/01; 117A/08; 117A/09; 117A/16; 117D/01; 117D/08; 117D/09; 117D/16
Lat/Long OENS-136.5000 -115.0000 70.0000 58.0000
Sujetscongélation du sol; glace fossile; températures au sol; climat; climat arctique; fluctuations climatiques; végétation; temperature; pergélisol; soulèvement par le gel; géologie des dépôts meubles/géomorphologie
Illustrationslocation maps; photographs; plots
ProgrammeSurveillance des variables climatiques, Géosciences de changements climatiques
Diffusé2015 08 06
Résumé(disponible en anglais seulement)
The Mackenzie Valley landscape is characterized by widespread permafrost terrain ranging from continuous on the Beaufort coastal plain to sporadic discontinuous in the south. The Geological Survey of Canada has maintained an active layer monitoring network in the Mackenzie Valley and Delta since the early 1990s for determination of annual maximum thaw depth and ground movement. The network currently includes 45 functional sites established in areas of representative vegetation and surficial material. Ten of these contribute to the Circumpolar Active Layer Monitoring network (CALM). Thaw tubes are utilized to determine maximum annual thaw penetration and maximum heave and subsidence of the ground surface. For some sites probing is also done on established CALM grids to measure thaw penetration at a given time and soil moisture content are also determined at specific grid nodes. Most sites are equipped with instrument to measure air and near-surface ground temperature. Active layer thickness in the Mackenzie Valley ranges from less than 50 cm in the north to greater than 100 cm in the southern region. North of Tsiigehtchic, departures from the 2003-2012 mean active layer thickness indicate thicker active layers in the 1990s followed by a thinning of active layers to 2005, with increasing thickness to 2012. North of treeline, a direct relation between air temperature and active layer thickness is evident where active layers in warmer years (1993, 1998, 2006) are on average ~3-9 cm thicker than the 2003-2012 mean; whereas cooler years such as 2004 are associated with thinner (average ~4 cm) active layer for most sites. South of treeline, greater site to site variability is observed and is a consequence of the insulating effect of the vegetation in summer and variable snow cover in winter. The moderating effect of ground insulation for these sites is apparent with a dampening of the active layer response to variations in air temperature although some of the warmer (1998) and cooler (2004) years are still noticeable with active layer on average ~5 cm thicker and ~6 cm thinner for both years respectively. Since 2009 active layers have become thicker in all regions of the Mackenzie Valley. Changes in the active layer thickness influences surface stability through thaw settlement, frost heaving and water ponding. These effects also have implication for the load bearing capacity of the ground and, in some circumstance, slope stability. The monitoring network provides baseline information that is helpful for land use planning decisions, engineering design of infrastructure and for understanding the impacts of a changing climate on a permafrost environment.
Résumé(Résumé en langage clair et simple, non publié)
La Commission géologique du Canada a entretenu depuis les années 1990 un réseau de sites d'observation du mollisol où sont mesurées la profondeur maximum du dégel et le mouvement de la surface du sol. L'épaisseur du mollisol est influencée par la température de l'air et l'isolation de la surface du sol par la végétation et la neige. Dans la vallée du Mackenzie, l'épaisseur du mollisol varie entre moins de 50 cm dans le nord à plus de 100 cm dans le sud. Depuis 2009, le mollisol s'est épaissit dans toutes les régions de la vallée du Mackenzie. Le réseau de site d'observation fournit des données de base utiles aux décisions de planification de l'utilisation du sol, à la conception technique de projets d'infrastructure et pour comprendre les impacts des changements climatiques sur un environnement pergélisolé.
GEOSCAN ID296513