Showing papers in "Agricultural and Forest Meteorology in 1997"

TL;DR: In this paper, the authors compare two methods of estimating growing degree-day (GDD) using TMAX and TMIN data, and show the differences which can result from using these two methods to estimate GDD, and demonstrate the need to report clearly which method was used in the calculations.

TL;DR: In this article, the authors analyzed evaporation time series data for different stations in India, and for the country as a whole, for different seasons on both a short-term (15 years) and longterm (32 years) basis for pan-evaporation and on a shortterm basis alone for potential evapotranspiration.

TL;DR: In this article, the point-to-area representativeness of micrometeorological flux measurements over inhomogeneous areas is discussed, especially pertaining to the selection and layout of sites and instrumentation in areas that do not comply with generally accepted standards of fetch and homogeneity.

TL;DR: In this paper, an empirical model was developed to improve the accuracy of Tn based humidity estimates using daily air temperature, annual precipitation and estimated daily potential evapotranspiration.

TL;DR: In this paper, the seasonal variation of the net carbon dioxide exchange between the ecosystem and the atmosphere and to understand the relative contributions of the vegetation and rhizosphere to these fluxes were examined.

TL;DR: In this article, a simple method of estimating potential evapotranspiration (PET) is presented that is suitable for assessing long-term changes in moisture regimes from limited climate data.

TL;DR: In this paper, the authors developed a mechanistic model that simulates the influence of various factors on volatilization, accounting for the transfers and equilibria in the topsoil and between the soil and the atmosphere.

TL;DR: In this article, a simple patch scale SVAT model still permits too many degrees of freedom in terms of fitting the model predictions to calibration or validation data; it is shown that good model fits may be achieved in many areas of the parameter space.

TL;DR: In this article, the authors measured the total forest evaporation (λE), understorey and environmental variables on nine summer days under different weather conditions in a 130-year-old stand of Larix gmelinii (Rupr.) Rupr.

TL;DR: In this article, solar radiation and air temperature near the soil surface and soil temperatures were measured from 15 June to 6 September 1993 in a 100m × 150m clear-cut, an 18m ×150m east-west strip, a 9m × 200m eastwest strip and a closed canopy trembling aspen forest near Chapleau, Ontario.

TL;DR: The long-term results of two of these studies are discussed in this paper, where the authors examined the impact of converting tussock grasslands to pine plantations using data collected from two catchments in the eastern uplands of southern New Zealand.

TL;DR: In this paper, a case-study data set of 2 years of daily climatic data (1989-1990) from 17 stations in the states of Nebraska, Kansas, and Colorado was used to compare alternative network designs and interpolation methods.

TL;DR: In this paper, a systematic analysis of the ventilation process in greenhouses was performed with the use of computational fluid dynamics (CFD) using a two-scale k-e turbulence model.

TL;DR: In this article, the seasonal course of the leaf area index (L) for both the overstory and understory was determined in a mature aspen forest in Prince Albert National Park, Saskatchewan, Canada.

TL;DR: In this paper, the Erosion Productivity Impact Calculator (EPIC) was used to simulate crop yields and water use in five representative farms in the Midwestern USA under a variety of climate scenarios.

TL;DR: In this paper, the authors present an analysis of the potential of forest plantations to store carbon in the high, middle, low-dry, and low-moist latitudes of the world.

TL;DR: In this paper, a systematic analysis of the natural ventilation process in greenhouses at no-wind and low-wind-speed conditions was performed with the use of Computational Fluid Dynamics (CFD).

TL;DR: In this article, surface renewal analysis was used to estimate the sensible heat flux density (H) over different crop canopies (grass, wheat, and sorghum) and the results were compared with eddy covariance measurements.

TL;DR: In this paper, a prototype yield estimation system was developed for the thirty provinces of Burkina Faso based on CERES-Millet, a crop simulation model of the growth and development of millet (Pennisetum spp.).

TL;DR: In this paper, the importance of clumping of vegetation, as defined by the fractional vegetative cover, for evaporation from soil and shrubs was investigated for a shrubland in southeastern Spain, which was dominated by the leguminous shrub Retama sphaerocarpa.

TL;DR: Crop growth Simulation results proved to be more useful for predicting national yield volumes than national yield, suggesting that both area and crop growth simulation results account for the annual variation of the yield volume.

TL;DR: In this article, a large-eddy simulation (LES) is used to investigate the canopy flow structure and the transfer of TKE, momentum and heat within and above a tall canopy in full leaf.

TL;DR: In this paper, a modelling approach for predicting soil surface temperature and soil evaporation is presented, which is based on the equations for heat flow at the soil surface and includes vapour diffusion and a semi-empirical correction function for the surface vapour pressure.

TL;DR: In this article, a study of poplar trees in an agroforestry system in the south of the UK was carried out and the results showed good agreement with the transpiration rate estimated using the Penman-Monteith equation with measured stomatal conductance.

TL;DR: In this article, the transpiration of 50 and 100-year-old coniferous stands was estimated on the basis of sap-flow measurements on 24 trees, 12 in each stand.

TL;DR: In this article, an Artificial Neural Network (ANN) model with a backpropagation architecture was developed to predict wetness on wheat flag leaves using environmental variables recorded at 0.5h intervals by an electronic datalogger.

TL;DR: In this paper, the impact of climate change on the yield and biomass of maize has been evaluated using two climate change models: Geophysical Fluid Dynamics Laboratory (GFDL) and United Kingdom Meteorological Office (UKMO), and two crop models: Crop Estimation through Resources and Environmental Synthesis (CERES), and Erosion/Productivity Impact Calculator (EPIC).

TL;DR: In this article, the authors measured evapotranspiration (ET) using a canopy chamber (CC) and Bowen ratio/energy balance (BREB) instrumentation and measured leaf CO2 uptake using a leaf chamber (LC), and, after accounting for soil CO2 fluxes, calculated leaf uptake with a CC and BREB instrumentation.