نتایج جستجو برای: soil hydraulic functions

تعداد نتایج: 692333  

2009
A. K. Guber R. E. Cady

1 S fl ow simulations have a multitude of applications at various scales, from irrigation scheduling to obtaining global climate change estimates. Modeling of fl ow in variably saturated soils requires water retention and hydraulic conductivity parameters that are impractical to measure for largescale projects. As opposed to saturated fl ow, the nonlinearity of the unsaturated fl ow constitutiv...

R. Sedghi S. Bairami Y. Hoseini

ABSTRACT-Determining hydraulic conductivity of soil is difficult, expensive, and time-consuming. In this study, Algorithm Genetic and geostatistical analysis and Neural Networks method are used to estimate soil saturated hydraulic conductivity using the properties of particle size distribution. The data were gathered from 134soil profiles from soil and lander form studies of the Ardabil Agricul...

Journal: :The New phytologist 2017
Xiaonan Tai D Scott Mackay William R L Anderegg John S Sperry Paul D Brooks

Elevated forest mortality has been attributed to climate change-induced droughts, but prediction of spatial mortality patterns remains challenging. We evaluated whether introducing plant hydraulics and topographic convergence-induced soil moisture variation to land surface models (LSM) can help explain spatial patterns of mortality. A scheme predicting plant hydraulic safety loss from soil mois...

Journal: :تحقیقات مهندسی کشاورزی 0
علی دیندارلو دانشجوی سابق کارشناسی ارشد علیرضا سپاسخواه استاد گروه آبیاری و زهکشی دانشکده کشاورزی، دانشگاه شیراز

solute transport processes are affected by soil pore water velocity distribution. pore size distribution, which can be used to infer pore water velocity distribution, can be estimated from a soil water retention curve (n). in this study, a solute breakthrough curve was simulated using soil hydraulic parameters in four different soils. to evaluate the proposed model, predictions were compared to...

1998
Katrin Schneeberger Jochen Willneff

Various applications such as meteorology, climatology or hydrology require information about the soil hydraulic properties over large areas. Microwave radiometry is a promising approach to gather this type of information. The microwave emission from soils is strongly affected by the roughness of the soil surface. This effect has therefore to be quantified to get a reasonable estimation of the h...

2006
H.-J. Vogel

A classical transport experiment was performed in a field plot of 2.5 m2 using the dye tracer brilliant blue. The measured tracer distribution demonstrates the dominant role of the heterogeneous soil structure for solute transport. As with many other published experiments, this evidences the need of considering the macroscopic structure of soil to predict flow and transport. We combine three di...

Journal: :پژوهش فیزیک ایران 0
رضا پورایمانی r puorimani university of arakدانشگاه اراک مرضیه مظلوم شهرکی m mazloom shahraki university of arakدانشگاه اراک

in this work, 137cs activity concentration of soil in five depths and in six meteorology stations in terms of bq/kg has been measured. for each thirty soil's samples, parameters such as kind of soil, density and hydraulic coefficient of transmission were determined. correlation coefficient between 137cs activity concentration and raining average, hydraulic coefficient of transmission and s...

H.R Eskandari J Bazargan

Filter is one of the main components of embankment dams. By a simple but effective performance, filter protects the dam against erosion and soil scouring in impervious core caused by leakage (piping) and makes it safe. Interaction between filter and erodible base soil is a complex phenomenon which is dependent upon several factors, and has challenged researchers for better understanding the fil...

2013
Yongchul Shin Binayak P. Mohanty

[1] Soil moisture (SM) at the local scale is required to account for small-scale spatial heterogeneity of land surface because many hydrological processes manifest at scales ranging from cm to km. Although remote sensing (RS) platforms provide large-scale soil moisture dynamics, scale discrepancy between observation scale (e.g., approximately several kilometers) and modeling scale (e.g., few hu...

1985
A. Loew

Land surface models (LSM) are widely used as scientific and operational tools to simulate mass and energy fluxes within the soil vegetation atmosphere continuum for numerous applications in meteorology, hydrology or for geobiochemistry studies. A reliable parameterization of these models is important to improve the simulation skills. 5 Soil moisture is a key variable, linking the water and ener...

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