New northern snowpack classification linked to vegetation cover on a latitudinal mega-transect across northeastern Canada

• Published in: Écoscience
• Main Authors: Royer, Alain, Domine, Florent, Roy, Alexandre, Langlois, Alexandre, Marchand, Nicolas, Davesne, Gautier
• Other Authors: Takuvik Joint International Laboratory ULAVAL-CNRS, Université Laval Québec (ULaval)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Centre d'Etudes Nordiques (CEN), Université Laval Québec (ULaval), Université du Québec à Trois-Rivières (UQTR), Université de Sherbrooke (UdeS), Université de Montréal (UdeM)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2021
• Subjects: snow-vegetation interaction; snowpack properties; Latitudinal gradient; snow cover classification; Gradient latitudinal; propriétés de la neige; interactions neigevégétation; classification de la couverture de neige; [SDE]Environmental Sciences; Arctic; Canada; Arctique*; Climate change; polar desert; Subarctic; subarctique*; Tundra
• Online Access: https://hal.science/hal-03427903; https://hal.science/hal-03427903/document; https://hal.science/hal-03427903/file/130-RoyerEcoscience2021.pdf; https://doi.org/10.1080/11956860.2021.1898775

International audience Changes in mass, extent, duration, and physical properties of snow are key elements for studying associated climate change feedbacks in northern regions. In this study, we analyzed snowpack physical properties along a 'mega' transect from 47°N to 83°N (4,000 km) in northeastern Canada, which includes marked transitions between ecozones from boreal forest to subarctic and arctic ecosystems. Our unique dataset of 391 detailed snowpits acquired over the last 20 years, complemented with snow data from weather stations, shows that snowpack properties such as snow water equivalent, snow depth, density, grain size and basal depth hoar fraction (DHF) are strongly linked to vegetation type. Based on these results, we propose an updated classification of snow types in three classes: boreal forest snow (47-58°N), tundra snow (58-74°N) and polar desert snow (74-83°N), which is more appropriate to the study area than the general north hemisphere classification commonly used. We also show that shrub presence along the transect contributes to a significant increase in DHF development which contributes most strongly to the thermal insulation properties of the snowpack. Overall, our analysis suggests that snow-vegetation interactions have a positive feedback effect on warming at northern latitudes. Les changements dans la masse, l’étendue, la durée et les propriétés physiques du manteau neigeux sont des éléments clés pour l’étude des rétroactions du changement climatique dans les environnements nordiques. Dans cette étude, nous avons analysé les propriétés physiques du couvert nival le long d’un « méga » transect de 47°N à 83°N (4000 km) dans le nord-est du Canada, comprenant des transitions marquées entre l’écozone de la forêt boréale et les écosystèmes subarctiques et arctiques. Notre ensemble de données uniques de 391 puits de neige détaillés, acquis au cours des 20 dernières années, enrichi de données de neige provenant de stations météorologiques, montre que les propriétés du manteau neigeux ...