EGU21-3539, updated on 20 Jun 2023
https://doi.org/10.5194/egusphere-egu21-3539
EGU General Assembly 2021
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

A Detailed and in Situ Assessment of the Snowpack Physical Properties in a Discontinuous Humid Boreal Forest

Benjamin Bouchard1,2, Daniel F. Nadeau1,2, and Florent Domine3,4
Benjamin Bouchard et al.
  • 1Laval University, Civil and Water Engineering Department, Quebec City, Canada (benjamin.bouchard.1@ulaval.ca)
  • 2CentrEau - Quebec Water Research Centre, Quebec City, Canada
  • 3Takuvik Joint International Laboratory, Quebec City, Canada
  • 4Laval University, Department of Chemistry, Quebec City, Canada

Boreal forests occupy a large fraction of the continental surfaces and receive a lot of solid precipitation in winter. Evergreen canopies are often represented as a single and homogeneous layer in hydrological and weather forecasting models. However, in reality, boreal canopies are composed of a rather complex mosaic of trees unevenly spaced apart, with gaps of various sizes. Therefore, mass and energy inputs to the snowpack show remarkable variability at small scales resulting not only in strong spatial heterogeneity in snow depth (SD) and snow water equivalent (SWE), but also in the vertical temperature gradient in the snow column (). Unlike SD and SWE, has been little documented in discontinuous needleleaf forests, despite its impact on snow cover metamorphism and on a range of physical properties of snow such as density (), specific surface area (SSA) and effective thermal conductivity (keff). This work investigates the snowpack underneath the canopy and inside small forest gaps using continuous measurements of SD and keff and weekly snow pit surveys during winter 2018-19 in a juvenile balsam fir stand of eastern Canada (47°17’18’’N, 71°10’05’’W). This site receives an average of almost 1600 mm of precipitation annually, including 40 % falling as snow. Snow cover typically lasts over 6 months. Observations show that less snow accumulates in the subcanopy and therefore  is more pronounced than inside the gaps. Moreover,  and SSA are lower underneath the canopy where faceted crystals are observed. Large  in that environment results in a decreasing keff over time. Overall, kinetic grain growth takes place in the subcanopy whereas settlement and isothermal conditions prevail inside the gaps. This research provides accurate observations of the snowpack in forested environments needed for a better representation of SWE, heat fluxes and ground thermal regime in hydrological and meteorological models.

How to cite: Bouchard, B., F. Nadeau, D., and Domine, F.: A Detailed and in Situ Assessment of the Snowpack Physical Properties in a Discontinuous Humid Boreal Forest, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-3539, https://doi.org/10.5194/egusphere-egu21-3539, 2021.

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