Satellite remote sensing of global change ecology from the leaf to the globe

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The global carbon (C) cycle is the exchange of C among the atmosphere, oceans, and land. The land C cycle is less understood than the atmosphere and ocean C cycles, contributing the largest error to the annual global C budget estimates. This is attributed largely to the lack of understanding of the magnitude of CO2 fertilization effect on plant growth and the changing sensitivity of plant growth to climate change. The proposed research program will integrate C cycle models and emerging ground and satellite technologies that directly measure photosynthesis for improved understanding of photosynthetic processes to narrow the land C cycle estimation uncertainty. The program proposes a pipeline of streamlined approaches for satellite remote sensing of global change ecology of terrestrial ecosystems that range from algorithm development and validation at the site level to improved product development at a regional scale, and global change impact study at a global scale. The overarching long-term vision of the research program is to quantify and attribute the roles of human influence and natural variability on satellite-detected changes in terrestrial ecosystem functioning. In light of the long-term vision, the following three contingent yet independent objectives will be achieved through the proposed 5-year program. At site level, ground-based sun-induced chlorophyll fluorescence (SIF) and hyperspectral measures of photosynthetic pigment pools will be used to parameterize chlorophyll light use behaviour at Turkey Point and Borden Forest Research Stations. At the regional scale, photosynthesis and phenology will be modelled for high latitude ecosystems using satellite-based hyperspectral and SIF observations. Finally, a global scale study of moisture stress and CO2 fertilization effects on plant growth will be conducted through model-data integration scheme that involves satellite and climate data archives, atmospheric CO2 concentration and C cycle models. The site level study will strengthen Canada's CO2 flux tower networks that are required for long-term environmental monitoring through instrumentation while improving our understanding of photosynthesis processes. In addition to its contribution towards narrowing the land C cycle estimation uncertainty, the proposed research program will build Canada's scientific capability in satellite remote sensing of global change and terrestrial ecosystems to support national climate change impact assessment and policy formulation. The regional focus on high latitude ecosystems will significantly benefit Earth science communities since knowing how these rapidly changing ecosystems are currently responding is paramount to predict what is yet to come. The high-latitude photosynthesis and phenology estimates can be used as benchmark data to quantify vegetation productivity and health responses to climate change, insects, wildfires and resource mining, all of which are emerging threats to Canada's forests.