Department of Environmental Sciences
Alexandre Roy (Regular member)
Introduction: All of Canada's ecosystems face seasonal freezing. Within the terrestrial cryosphere, spatial patterns and timing of landscape freeze/thaw (FT) state transitions are highly variable but play crucial roles in modulating energy, water, and carbon and nitrogen fluxes and budgets. For instance, in boreal forests, an important carbon storage, the annual carbon balance, and the stability of the soil carbon pool in Canada's ecosystems varies according to the interannual variability of FT cycles. Given the importance of FT processes in Canada, methods for observing terrestrial FT states are critical to improve understanding and monitoring of various climatological, biogeochemical and hydrological processes. Objectives: The main goal of my Ph.D. is to develop a new passive microwave multisensory FT algorithm using multi-frequency passive observations to improve carbon fluxes monitoring during the shoulder seasons in frozen environments in North America. Study sites: My project will develop and integrate a large data record of soil temperature and soil moisture data from many of Canada's landcover types, including soil temperature networks across the Taiga Plains ecozone of the Northwest Territories, two large scale networks of soil moisture, and soil FT near Kenaston, southern Saskatchewan and in boreal forest in the Boreal Ecosystem Research and Monitoring Sites, a soil temperature network in high Arctic environment close to the town of Cambridge Bay, two soil temperature networks in southern Québec at the St-Marthe experimental watershed and the St-Maurice site, a soil temperature network on the Bylot Island, and three soil temperature networks in Northern Québec boreal forest (Lake Chisapaw, Baie-James Lemoyne and Forêt Montmorency). Material and methods: My project will develop and validate improved FT algorithms based on combined SMAP-SMOS and AMSR2 observations. The validation of the new algorithm will be based on a unique soil temperature network across 13 sites in various Canada's landcover types. The FT algorithm will then be applied across North American to create a daily passive microwave FT product. The product will then be available to the international scientific community via the National Snow and Ice Data Center. The timing of the FT cycles will then be compared to the start and end of photosynthesis based on eddy covariance carbon fluxes measurements network. The comparison will allow evaluating the potential of the new product to monitor the growing season in North America. Expected results: We will try to provide the best satellite FT products for hydrological, infrastructure, climatological, and climate change assessment applications. The developed FT product could also help to improve soil state in the CLASS-CTEM Land surface model. Finally, FT products also could contribute to spring flood prediction, especially in Quebec, to establish mitigation and adaptation strategies.
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