Base de données de recherche des TNO

Régions: North Slave Region

étiquettes: physical sciences, active layer, climatology, climate change, greenhouse gases, atmospheric sciences, meteorology

Objectif(s): To study how important greenhouse gases, carbon dioxide and methane, are exchanged between tundra surfaces and the atmosphere.

Description du projet: The objective of this study is to study how important greenhouse gases, carbon dioxide and methane, are exchanged between tundra surfaces and the atmosphere. These exchanges will be measured over various tundra types and relate them to environmental variables such as soil properties and weather, in hopes of understanding more about how future climate change will impact the land surface and how these impacts might influence the climate itself. This research is part of a long-term study of tundra-atmosphere interactions at Daring Lake. The primary platform for measuring the CO2 exchange is an eddy covariance tower, which has been established for the past several summers at an upland tundra site and in a wet sedge fen, and occasionally at a shrub site. These towers measure concentrations of the carbon gases in the atmosphere, wind and other meteorological variables, as well as soil temperatures and moisture. The tower equipment runs automatically and is visited a few times a week for data retrieval and maintenance. Daily (or weekly) measurements to vegetation growth and active layer depth (i.e., seasonal permafrost thawing) are made around each of the sites. There is virtually no disturbance of the surrounding tundra. As well, CO2 is measured from small (0.5 x 0.5 m) plots on various tundra communities using a manual chamber system. These measurements help in understanding how the small-scale heterogeneity of the tundra vegetation influences the tower measurements. In addition, these measurements support the tower flux measurements, especially the new CH4 eddy flux tower equipment that was test run in 2009 and will be operated in future years. Some vegetation plots (5 per location) are manipulated by clipping the vegetation in order to measure the soil only component of the flux and to measure total biomass and leaf area index. These measurements are conducted weekly and confined to small patches of tundra not far from the towers. The measurements will take place between May and September, encompassing the summer growing period. Daring Lake Research Station hosts an annual 'Science Camp' for NWT high school students. Each year the research group assists the camp by giving demonstrations of the research and tours of the sites and experiments. Members of the research group have been involved with this activity for the past several years and this will continue in the future. As well, on occasion members of the group have given public lectures in Yellowknife while traveling to and from the site. During a science meeting at Yellowknife in early May 2009, Peter Lafleur gave public talk at the Prince of Whales Museum on the Daring Lake research. Copies of any papers that result from the research will be forwarded to the Aurora Research Institute. The research team will advance information to any communities or other groups wishing information on this research, upon request. The team will participate in the Daring Lake Science Camp. The team would be happy to make visits to communities for presentations and discussions concerning this research when invited and where possible. The fieldwork for this study will be conducted from April 29, 2011 to September 30, 2011.