A new observational approach is presented to approximate the uncertainty (scatter or error variance) in 1-h averaged turbulence fluxes from eddy-covariance measurements. The uncertainty includes potential contributions from instrument problems,… More
We monitored sap flow and estimated diurnal changes in transpiration rates of two trembling aspen (Populus tremuloides Michx.) stands, located in the southern boreal forest and aspen parkland of Saskatchewan,… More
Quantifying isotopic CO2 exchange between the biosphere and atmosphere presents a significant measurement challenge, but has the potential to provide important constraints on local, regional, and global carbon cycling. Past… More
For two species of oak, we determined whether increasing atmospheric CO2 concentration (Ca) would decrease leaf mitochondrial respiration (R) directly, or indirectly owing to their growth in elevated Ca, or… More
Effective leaf area index is routinely quantified with optical instruments that measure gap fraction through the probability of beam penetration of sunlight through the vegetation. However, there have been few… More
Tower and aircraft data from a number of field studies are analyzed to: (1) estimate the roughness lengths for local and area-averaged momentum fluxes over various surface types; (2) examine… More
The directional thermal infrared exitance distributions of a 21.5-m-tall leafless deciduous forest were measured using a rotating 7-detector array suspended 33 m above the forest floor. These distributions are presented… More
Rising air temperatures are believed to be hastening heterotrophic respiration (Rh) in arctic tundra ecosystems, which could lead to substantial losses of soil carbon (C). In order to improve confidence… More
To determine factors controlling the carbon dynamics of an intensively managed landscape, we measured net CO2 exchange with the atmosphere using eddy covariance and soil CO2 fluxes using static chambers… More
Leaf area index (LAI) is an important variable for climate modeling, estimates of primary production, agricultural yield forecasting, and many other diverse studies. Remote sensing provides a considerable potential for… More