Showing papers in "Agricultural and Forest Meteorology in 2000"

TL;DR: In the Southern Great Plains 1997 Hydrology Experiment, four different types of eddy-covariance systems were set up side-by-side and all of them under-measured sensible and latent heat fluxes by similar amounts.

TL;DR: Stomatal conductance (gs) and transpiration (E) are often positively correlated with the hydraulic conductance of the soil-leaf continuum (ksl) as discussed by the authors.

TL;DR: In this article, a simple analytical formula is developed for estimating the frequency attenuation of eddy covariance fluxes due to sensor response, path-length averaging, sensor separation, signal processing, and flux averaging periods.

TL;DR: In this article, the authors present an overview of crop modeling and applications of crop models, and the significance of weather related to these applications, and they also define standard file formats for weather and other input data; this will expand the applicability of weather data by different models.

TL;DR: In this paper, the components of the surface energy balance were measured for three years over a broadleaved deciduous forest using the eddy covariance technique, and the most influential effect on annual fluxes was the occurrence and extent of drought, with lesser control exerted by differences in the timing of leaf expansion and leaf senescence.

TL;DR: In this paper, the first full year of measurements (1998−1999) of above canopy CO 2 and energy fluxes at the AmeriFlux site in the Morgan-Monroe State Forest, IN, USA, are presented.

TL;DR: In this paper, the authors measured sap flow, vapour fluxes, throughfall and soil water content in a young beech stand growing at low elevation, in the Hesse forest.

TL;DR: In this article, two methods for elevation-dependent spatial interpolation of climatic data from sparse weather station networks were compared and the comparison revealed lower root mean square error (RMSE) for ANUSPLIN in 70 out of 72 months (three variables for 12 months for both regions).

TL;DR: In this article, the eddy covariance method was used to measure CO2, water vapor, and sensible heat in young ponderosa pine plantations in the Sierra Nevada Mountains (CA) over two growing seasons.

TL;DR: In this paper, the fraction of tree transpiration water derived from unsaturated soil zone and groundwater in a riparian forest was quantified for Populus fremontii, Salix gooddingii, and Prosopis velutina across a gradient of groundwater depth and streamflow regime on the San Pedro River in southeastern Arizona, US.

TL;DR: In this article, the authors investigate climate variability in Bulgaria during the 20th century and determine the overall impact of climate change on agriculture by using Decision Support System for Agrotechnology Transfer (DSSAT) Version 3.5.

TL;DR: In this paper, the Bowen ratio energy balance method was used to analyze microwave measurements from 1992 to 1994 in Naiman (lat. 42°58′N, long. 120°43′E, 345m asl), Inner Mongolia, China to elucidate desertification mechanisms.

TL;DR: Sano et al. as discussed by the authors designed an experiment to investigate the sensitivity of C-band SAR backscatter (σ0) to surface soil moisture (θs) in a semi-arid rangeland and to test a data-fusion approach based on both optical (Landsat TM) and radar (ERS-2 SAR) measurements to improve regional estimates of surface moisture content.

TL;DR: In this paper, the authors evaluate the behavior of two empirical models based on the difference between maximum and minimum temperatures and compare results with a model based on sunshine hours, and conclude that empirical models are easy to use in any location if the parameters are correctly adjusted.

TL;DR: In this paper, a helicopter-mounted portable spectroradiometer and continuous eddy covariance data were used to evaluate the photochemical reflectance index (PRI) as an indicator of canopy photosynthetic light use efficiency (LUE) in four boreal forest species during the Boreal Ecosystem Atmosphere experiment (BOREAS).

TL;DR: In this article, the role of floodwater in controlling the exchanges of CO 2 and CH4 from soil, floodwater and the canopy in intermittently flooded rice paddies was assessed.

TL;DR: The Bowen ratio energy balance (BREB) method is a micrometeorological method often used to estimate latent heat flux because of its simplicity, robustness, and cost.

TL;DR: In this paper, the use of meteorological information for crop evapotranspiration and water supply from rain has been investigated in both irrigated and rain-fed agriculture and the new procedures and guidelines have been recently published in the FAO Irrigation and Drainage series and include the adoption of the Penman-Monteith approach as the new standard for determining reference crop ETo calculations.

TL;DR: In this article, a simple, analytical model for canopy resistance to canopy-atmosphere gas exchange was developed for incorporation into regional-scale land-surface parameterizations, which exploits the conservative nature of canopy light-use efficiency (LUE) in carbon assimilation.

TL;DR: In this article, the mean behavior of mass and energy exchange below forest canopies was analyzed using eddy covariance measurements and a micrometeorological soil/plant/atmosphere exchange model and the results showed that the partitioning of solar energy into sensible, latent and soil heat flux is affected by atmospheric thermal stratification, surface wetness and the thickness of the litter layer.

TL;DR: In this paper, a ventilated open soil chamber was used to measure forest floor CO 2 efflux in a mixed boreal spruce and pine forest in central Sweden during 1996.

TL;DR: In this paper, the spectral distribution of radiation was estimated by combining different literature data and the spectral sensitivity of a typical pyranometer using available data for spectral transparency of glass domes and spectral reflectivity of black paints.

TL;DR: In this paper, a pseudo-invariant object method was employed to adjust multitemporal images acquired with Landsat TM, SPOT 4 VEGETATION, and aircraft-based sensors to map the spatial and temporal distribution of fractional green vegetation cover and green leaf area index.

TL;DR: In this article, the energy balance components were measured above the ground surface of a temperate deciduous forest over an annual cycle using the eddy covariance technique, and the dominant response to seasonal changes in net radiation was through corresponding changes in the sensible heat flux.

TL;DR: In this paper, surface energy and water fluxes were measured for an annual cycle over two dominant types of vegetation in the riparian floodplain of the San Pedro River in southeastern Arizona.

TL;DR: In this paper, a series of interdisciplinary experimental campaigns were conducted in 1997 in the San Pedro Basin in southeastern Arizona to estimate seasonal riparian evapotranspiration (ET).

TL;DR: The leaf stomata were an effective NH3 sink, whereas the leaf litter dominates night-time emissions and the silique-layer (probably) daytime emissions, and the 3-layer model appears to be the mechanistically more accurate description.

TL;DR: In this article, the authors investigated the role of the xylem of a spruce tree in the shrinkage of the tree's stem and root radius in the presence of mild winters.

TL;DR: In this paper, the authors used the heat-pulse velocity technique to estimate transpiration in 12 such forest patches along a perennially flowing reach of the San Pedro River in southeastern Arizona, USA during five periods from April to October 1997.