Base de données de recherche des TNO

Régions: Dehcho Region

étiquettes: physical sciences, permafrost, vegetation, climate change, carbon dioxide, peatlands, methane, boreal forests

Objectif(s): To determine the net effect of permafrost thawing-induced biophysical and biogeochemical feedbacks to the climate system.

Description du projet: Through this project the research team will address the following objectives: 1) determine the net effect of permafrost thawing-induced biophysical and biogeochemical feedbacks to the climate system; 2) determine how these two types of feedback differ between the sporadic and discontinuous permafrost zones; 3) determine if s the reported decrease (increase) in net carbon dioxide (methane) exchange based on plot- (<1m2) and ecosystem-scale (1km2) flux measurements made over mostly tundra sites in the continuous permafrost zone generalizable to boreal forest and peatland ecosystems with sporadic and discontinuous permafrost; and, determine if the net ecosystem carbon dioxude and methane exchanges of boreal forest and peatland ecosystems in different permafrost zones respond differently to higher/lower precipitation inputs than, for example, thawing/growing season lengths. The core component of this project at Smith Creek is a 15-m micrometeorological tower on which the eddy covariance system and supporting instrumentation will be installed. The eddy covariance system comprises a three-dimensional sonic anemometer to measure wind velocities, an open-path gas analyzer for carbon dioxide and water vapour concentrations and an open-path gas analyzer for methane concentrations. The covariance of the vertical wind velocities and the different concentrations will allow for the calculation of the respective fluxes between the landscape and the atmosphere. These quasi-continuous measurements are complemented by repeated surveys of surface and frost table topography, vegetation, micrometeorological and environmental conditions to understand the influence of spatial and temporal permafrost dynamics on vegetation composition and structure, by remote sensing-based footprint analysis to characterize landscape heterogeneity/homogeneity, and by continuous near-surface remote sensing to interpret eddy covariance measurements in a phenological framework. The vulnerability of permafrost landscapes to climate change has been widely acknowledged but the understanding of its consequences for boreal forest ecosystem structure, functioning and services is still insufficient. Based on an extensive network of contacts across the Northwest Territories, research results of this project will be presented informally in public meetings to local communities but also to local federal and territorial government agencies. The fieldwork for this study will be conducted from April 15, 2017 to December 31, 2017.