Laboratory for Remote Sensing of Earth and Environmental Systems

Paul in the field Arctic tundra and boreal forest environments account for a large proportion of Canada's land surface and are important systems within the context of global climate change research. These northern environments are thought to be particularly sensitive to changes in climate, yet it remains unclear as to how these environments will respond. It is expected that any alterations in arctic tundra and boreal forest ecosystem function associated with increased temperatures will be expressed through shifts in plant phenology (i.e., vegetation growth patterns with season), species composition, and abundance. Remote sensing provides a means for monitoring these shifts, with the potential to characterize biophysical variables that control carbon fluxes over landscapes or regions.

Our research focuses on the estimation and mapping of biophysical variables for northern terrestrial landscapes. In addition to the obvious impacts of increasing air temperatures, there are a number of factors that serve as controls on vegetation growth in the Canadian Arctic, including soil moisture, nutrient availability, soil type and topography/micro-topography, some of which are also impacted by warming temperatures. The variability and distribution of these environmental controls contribute to a highly heterogeneous vegetation cover. High spatial resolution remote sensing provides an opportunity to estimate and monitor this variability, with the potential to quantify biophysical variables that control carbon fluxes over large areas. However, detailed in situ studies are required for calibration and validation of appropriate remote sensing models to estimate these variables. The focus of our research is on modeling biophysical variables at multiple scales across a latitudinal gradient (~63°-77°N) for the Canadian Arctic; serving as a temperature gradient of approximate 10°C for mean-July temperatures - a surrogate for a warming climate. We are carrying out this research at Cape Bounty (75ºN), Melville Island; Boothia Peninsula (71ºN); and the Apex River, Baffin Island (63ºN), Nunavut.

Estimating biophysical variables for forested ecosystems represents a three-dimensional problem given the structural components of a forest ecosystem are distributed vertically as well as horizontally. Our current emphasis in the forest sector is on the modelling of biophysical variables (e.g. volume, biomass) and services (habitat suitability) for forest ecosystems using airborne light detection and ranging (LiDAR). LiDAR captures three-dimensional information on forest structure (e.g., canopy height) and provides significant potential for volume and biomass estimation using forest allometry. Analysis and development of LiDAR height and density metrics is being conducted to determine how three-dimensional surfaces of the forest canopy and terrain can be created and utilized to predict the structural (and functional) nature of forest stands. We are currently involved in a national research program examining the modelling of forest biophysical variables as well as the transferability of these models across different forested environments.