in order to study of the radiation interception and red to far red light ratio variations in sunflower hybrids under drought stress, nine sunflower hybrids in three separate experiments were compared as randomized complete block designs with three replications at the research station of seed and plant improvement institute in karaj in 2006. first experiment (control) was irrigated based on 60 m...

The temporal variability of interception losses was measured for contrasting forest communities in the southeastern United States. Throughfall was measured simultaneously at Fort Benning in western Georgia for the five forest communities that are characteristic of the region. The measured interception losses over the study period were 22.3, 18.6, 17.7, 17.6, and 17.4% of the total precipitation...

The estimation model was constructed to estimate the evapotranspiration and canopy interception from the forest stand using the parameters showing the forest structure such as stem density, tree height and leaf area index. This model is expected to have the ability to estimate the effect of forest management such as stem thinning and leaf amount control. Comparing the calculated rate by this mo...

Net canopy interception (Inet) during rainfall in an old-growth Douglas-fir–western hemlock ecosystem was 22.8 and 25.0% of the gross rainfall (PG) for 1999 and 2000, respectively. The average direct throughfall proportion (p) and canopy storage capacity (S) derived from high-temporal resolution throughfall measurements were 0.36 and 3.3 mm, respectively. Derived values of S were very sensitive...

The interception and redirection of rainfall by vegetation has implications for many fields such as remote sensing of soil moisture, satellite observation of rainfall, and the modeling of runoff, climate, and soil erosion. Although the modeling of rainfall partitioning by forests has received attention in the past, partitioning caused by crops has been overlooked. The present work proposes a tw...

Precipitation exhibits significant spatial variability at scales much smaller than the typical size of climate model grid cells. Neglecting such subgrid-scale variability in climate models causes unrealistic representation of land–atmosphere flux exchanges. It is especially problematic over densely vegetated land. This paper addresses this issue by incorporating satellite-based precipitation ob...

Evapotranspiration (ET) is the primary component of the forest hydrologic cycle, which includes plant transpiration, canopy rainfall interception, and soil evaporation. Quantifying ET processes and potential biophysical regulations is needed for assessing forest water management options. Loblolly pines are widely planted in the coastal plain of the Southeastern US, but their water use is rarely...

Light models for vegetation canopies based on the turbid medium analogy are usually limited by the basic assumption of random foliage dispersion in the canopy space. The objective of this paper was to assess the effect of three possible sources of non-randomness in tree canopies on light interception properties. For this purpose, four threedimensional (3-D) digitized trees and four theoretical ...

Accurately quantifying the vegetation rainfall interception at a high resolution is critical for rainfall-runoff modeling and flood forecasting, and is also essential for understanding its further impact on local, regional, and even global water cycle dynamics. In this study, the Remote Sensing-based Gash model (RS-Gash model) is developed based on a modified Gash model for interception loss es...