Stable isotopes provide insight into ecosystem carbon cycling, plant physiological processes, atmospheric boundary-layer dynamics, and are useful for the integration of processes over multiple scales. Of particular interest is the… More
Separation of the net ecosystem exchange of CO2 (F) into its component fluxes of net photosynthesis (FA) and nonfoliar respiration (FR) is important in understanding the physical and environmental controls… More
CO2 transport processes relevant for estimating net ecosystem exchange (NEE) at the Niwot Ridge AmeriFlux site in the front range of the Rocky Mountains, Colorado, USA, were investigated during a… More
The construction and deployment of a portable trace-gas measurement system (TGaMS) is described. The air-collection system (dubbed HYDRA) collects air samples from 18 different locations and was connected to either… More
Snowpack temperatures from a subalpine forest below Niwot Ridge, Colorado, are examined with respect to atmospheric conditions and the 30-min above-canopy and subcanopy eddy covariance fluxes of sensible Qh and… More
Sonic anemometers simultaneously measure the turbulent fluctuations of vertical wind (w’) and sonic temperature (Ts’), and are commonly used to measure sensible heat flux (H). Our study examines 30-min heat… More
Most terrestrial carbon sequestration at mid-latitudes in the Northern Hemisphere occurs in seasonal, montane forest ecosystems1. Winter respiratory carbon dioxide losses from these ecosystems are high, and over half of… More
The respiratory loss of CO2 from soil microbes beneath winter snow in forests from cold climates can significantly influence the annual carbon budget. We explored the magnitude of winter soil… More
The eddy covariance technique, which is used in the determination of net ecosystem CO2 exchange (NEE), is subject to significant errors when advection that carries CO2 in the mean flow… More
Eddy covariance measurements of the surface energy balance and carbon dioxide exchange above high-elevation (3,480 m above sea level) alpine tundra located near Niwot Ridge, Colorado, were compared to simultaneous… More