This paper presents the design and evaluates the performance of a double-walled electrically aspirated radiation shield for thermometers measuring air temperature and its gradients in the atmospheric surface layer. Tests were performed to quantify its solar radiation error and wake production, and to characterize the observer effect of the forced...
We present a novel technique to simultaneously measure wind speed (U) at thousands of locations continuously in time based on measurement of velocity-dependent heat transfer from a heated surface. Measuring temperature differences between paired passive and actively heated fiber-optic (AHFO) cables with a distributed temperature sensing system allowed estimation of...
We investigated an alternative means for quantifying daytime ecosystem respiration from eddy-covariance data in three forests with different canopy architecture. Our hypothesis was that the turbulent transport by coherent structures is the main pathway for carrying detectable sub-canopy respiration signals through the canopy. The study extends previously published work by...
We sought to improve net ecosystem exchange (NEE) estimates for a tall, dense, mature Douglas-Fir forest in the Oregon Coast range characterized by weak flows, systematic wind directional shear, and limited turbulent mixing throughout the diurnal period. We used eddy covariance (EC) observations at two levels and concurrent biological measurements...
Five years of eddy-covariance and other measurements at a mature ponderosa pine forest and a nearby young plantation are used to contrast the carbon fluxes for long-term averages, seasonal patterns, diel patterns and interannual variability, and to examine the differing responses to water-stress. The mature forest with larger leaf area...
We present a novel approach based on fibre-optic distributed temperature sensing (DTS) to measure the two-dimensional thermal structure of the surface layer at high resolution (0.25 m, ≈ 0.5 Hz). Air temperature observations obtained from a vertically oriented fibre optics array of approximate dimensions 8 m x 8 m and...
Headwater streams comprise nearly 90% of the total length of perennial channels in global catchments. They mineralize organic carbon entering from terrestrial systems, evade terrestrial carbon dioxide (CO₂ ), and generate and remove carbon through in-stream primary production and respiration. Despite their importance, headwater streams are often neglected in global...
Full Text:
. Dosch2, H. Corson-Rikert2, L. R. Ashkenas4, 5
R. Pennington2, and C. K. Thomas2,5 6
1Department of
Headwater streams comprise nearly 90% of the total length of perennial channels in global catchments. They mineralize organic carbon entering from terrestrial systems, evade terrestrial carbon dioxide (CO₂ ), and generate and remove carbon through in-stream primary production and respiration. Despite their importance, headwater streams are often neglected in global...
Full Text:
, Linda R. Ashkenas4, Robert Pennington2, and ChristophK. Thomas2,5
1Department of Forest Engineering
Headwater streams comprise nearly 90% of the total length of perennial channels in global catchments. They mineralize organic carbon entering from terrestrial systems, evade terrestrial carbon dioxide (CO₂ ), and generate and remove carbon through in-stream primary production and respiration. Despite their importance, headwater streams are often neglected in global...
Budburst is a key adaptive trait that can help us understand how plants respond to a changing climate from the molecular to landscape scale. Despite this, acquisition of budburst data is constrained by a lack of information at the plant scale on the environmental stimuli associated with the release of...