This paper investigates the effect of sub-grid rainfall variability on the simulation of land surface hydrologic processes of three regions (Europe, Africa and Amazon) with contrasting precipitation and vegetation characteristics. The sub-grid rainfall variability is defined in terms of the rainfall coverage fraction at the model’s grid cells, and the statistical distribution of rain rates with...

A 2-year study was conducted to determine the relationships between plant canopy photosynthesis, canopy light interception, and plant productivity of cotton (Gossypium hirsutum L.) exhibiting differing leaf morphologies. The near-isogenic lines were from a single background (MD 65-11) and represented the leaf shapes Normal (small leaf lobing), Sub-Okra (intermediate leaf lobing), Okra (large le...

In the southeastern United States, many forest managers are interested in restoring longleaf pine (Pinus palustrisMill.) to upland sites that currently support loblolly pine (Pinus taeda L.). We quantified the effects of four canopy treatments (uncut Control; MedBA, harvest to 9 m2·ha−1; LowBA, harvest to 5 m2·ha−1; and Clearcut) and three cultural treatments (NT, no treatment; H, herbicide rel...

to investigate the effect of plant density and supplemental irrigation on agronomic characteristics, chlorophyll content and light interception beneath the canopy of three chickpea genotypes under dryland conditions, an experiment was conducted at research station of lorestan agricultural research center located at chegini, khoramabad, during 2004-2005. the study was conducted using a split-spl...

The amount of photosynthetically active radiation (PAR) absorbed by a canopy (APAR) is an important driving variable for vegetation processes such as photosynthesis. PAR extinction in clumped canopies of shortgrass ecosystems is the focus of this paper. Directional gap fractions estimated at peak biomass on several Mexican shortgrass ecosystems with a hemispherical radiation sensor (Li-Cor, LAI...

This paper reviews the development of the stochastic interception model from the original, single-layer, drop-size-dependent model to the two-layer model that recognizes that vegetation canopies are wetted through both the primary impact of raindrops to the top layer of the canopy and secondary impacts from drops falling from the vegetation to lower layers of the canopy. It is shown that drop v...

This report describes a system for integrating photosynthetically active radiation (PAR) using fi beroptics. Many photoelectric sensors or 1-m-long line sensors that integrate individual interception points for spatial averaging were replaced with fi beroptics, which integrate interception points. Depending on the positioning of optical fi bers and the amount of fi bers terminated at a PAR sens...

The three-dimensional structure of a coniferous shoot gives rise to multiple scattering of light between the needles of the shoot, causing the shoot spectral reflectance to differ from that of a flat leaf. Forest reflectance models based on the radiative transfer equation handle shoot level clumping by correcting the radiation attenuation coefficient with a clumping index. The clumping index ca...

we estimated the rainfall interception loss (i), canopy storage capacity (s), the ratio of mean evaporation rate from the wet canopy () over the mean rainfall intensity () (mm h-1) (), and free throughfall coefficient (p) in a fraxinus rotundifolia mill. stand located in an afforested park land in a semiarid region of iran. for each storm event, i was calculated as the gross rainfall (gr) minus...

Interception of rainfall by forest canopies and its evaporation back to the atmosphere is an important component hydrological balance. We quantify influence six mature forests at two coastal one southern interior locations in British Columbia on interception loss. Drainage from canopy was measured with throughfall troughs stemflow collars that emptied into tipping buckets monitored data loggers...