A multi-year, multi-technique study was conducted to measure evapotranspiration and its components within an uneven-aged mixed deciduous forest in the Southeastern United States. Four different measurement techniques were used, including soil water budget (1 year), sap flow …
Journal: Agricultural And Forest Meteorology, Volume 106 (2): 153-168 (2001), ISBN . DOI: 10.1016/s0168-1923(00)00199-4 Sites: US-WBW
This paper reports the first effort to include carbon, water, and heat exchange in a Large Eddy Simulation (LES) model for 3D canopy flows with dynamic response of leaf temperature and stomatal aperture. The LES model simulates eddy motion from 3D, transient integration …
Journal: Advances In Water Resources, Volume 24 (9-10): 1103-1118 (2001), ISBN . DOI: 10.1016/s0309-1708(01)00042-2 Sites: US-Dk3
The largest biological fractionations of stable carbon isotopes observed in nature occur during production of methane by methanogenic archaea. These fractionations result in substantial (as much as ≈70‰) shifts in δ13C relative to the initial substrate. We …
Journal: Proceedings Of The National Academy Of Sciences, Volume 98 (10): 5833-5837 (2001), ISBN . DOI: 10.1073/pnas.101129798 Sites: US-Blo
At a deciduous forest in the southeast United States (Walker Branch Watershed, Oak Ridge, Tennessee), as at other sites with tall vegetation and/or complex terrain, it is difficult to temporally integrate …
Journal: Journal Of Geophysical Research: Atmospheres, Volume 106 (D24): 34167-34178 (2001), ISBN . DOI: 10.1029/2001jd000624 Sites: US-WBW
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 the applicability of the ψ-stability formulations of Paulson and Dyer for momentum fluxes; (3) investigate the possibility …
Journal: Agricultural And Forest Meteorology, Volume 108 (4): 265-279 (2001), ISBN . DOI: 10.1016/s0168-1923(01)00250-7 Sites: CA-Man, CA-Oas, CA-Obs, CA-Ojp, CA-SJ3
Accurate estimates of leaf area index (LAI) and leaf angle distribution (LAD) are important for estimating the exchange of energy and gases in vegetative canopies. Direct estimates of LAI and LAD are laborious, time consuming and often times destructive. Stewart and Dwyer [Agric. For. Meteorol. 66 (1993) 247] introduced a mathematical …
Journal: Agricultural And Forest Meteorology, Volume 108 (1): 45-53 (2001), ISBN . DOI: 10.1016/s0168-1923(01)00219-2 Sites: US-KFB, US-Kon
Eddy covariance measurements of the carbon dioxide flux from an ombrotrophic bog near Ottawa, Canada, were made between June 1, 1998, and May 31, 1999. Net ecosystem exchange of CO2 (NEE) showed …
Journal: Journal Of Geophysical Research: Atmospheres, Volume 106 (D3): 3071-3081 (2001), ISBN . DOI: 10.1029/2000jd900588 Sites: CA-Mer
The energy balance components were measured above the ground surface of a temperate deciduous forest over an annual cycle using the eddy covariance technique. Over a year, the net radiation at the forest floor was 21.5% of that above the canopy, but this proportion was not constant, primarily because of the distinct phenological …
Journal: Agricultural And Forest Meteorology, Volume 102 (2-3): 83-103 (2000), ISBN . DOI: 10.1016/s0168-1923(00)00124-6 Sites: US-WBW
The vertical structure of the flow in the old aspen canopy in BOREAS is examined in terms of thermocouple profiles and sonic anemometers above, within, and below the aspen canopy. The data are composited for different periods in order to isolate seasonal changes of the canopy and sun angle. On clear nights, a strong surface …
Journal: Agricultural And Forest Meteorology, Volume 101 (1): 67-78 (2000), ISBN . DOI: 10.1016/s0168-1923(99)00161-6 Sites: CA-Oas
The components of the surface energy balance were measured for 3 years over a broadleaved deciduous forest using the eddy covariance technique. Within years, the magnitude and distribution of fluxes was controlled by seasonal changes in solar radiation, drought, as well as leaf emergence and senescence. Evapotranspiration increased …
Journal: Agricultural And Forest Meteorology, Volume 100 (1): 1-18 (2000), ISBN . DOI: 10.1016/s0168-1923(99)00088-x Sites: US-WBW