نتایج جستجو برای: modified penman equation

تعداد نتایج: 472208  

Journal: :آب و خاک 0
حسین انصاری حوریه مرادی

abstract evapotranspiration as one of the most important components of the hydrologic cycle, plays a key role in water resources management, crop yield simulation and irrigation scheduling. therefore, presenting a low cost and precision model is very essential for calculations of hourly eto. although, there are empirical formulas, their performances are not all satisfactory due to the complicat...

ژورنال: علوم آب و خاک 2013

Quantitative evaluation of evapotranspiration on a regional scale is necessary for water resources management, crop production and environmental assessments in irrigated lands. In this study, in order to estimate ETo and because of few synoptic stations and also little recorded meteorological data in North Khorasan Province, Iran, with arid and semi-arid climate, 7 stations from neighboring pro...

Journal: :Tree physiology 2002
Jane L Medhurst Michael Battaglia Christopher L Beadle

We investigated changes in the pattern of water use of an 8-year-old Eucalyptus nitens (Deane and Maiden) Maiden plantation soon after thinning. Sap flow sensors using heat pulse technology were deployed across three stands thinned to a final density of 100, 250 or 600 trees ha-1 plus an unthinned control (1250 trees ha-1). Changes in the relationship between tree size and daily water use were ...

Journal: :تحقیقات آب و خاک ایران 0
علی رحیمی خوب دانشیار، پردیس ابوریحان سید محمودرضا بهبهانی دانشیار، پردیس ابوریحان

most weather stations in iran have been installed in arid areas, far from agricultural lands. therefore, the data gathered are not valid for estimating reference evapotranspiration. the advantage of satellite imagery is the coverage of a wide surface region from where information regarding agricultural areas can be obtained. according to this issue, researchers have converted the penman monteit...

Journal: :bulletin of the iranian mathematical society 0
m. behroozifar department of mathematics‎, ‎faculty of basic sciences‎, ‎babol noshirvani university of technology‎, ‎babol‎, ‎mazandaran‎, ‎iran. f. ahmadpour department of mathematics‎, ‎faculty of basic sciences‎, ‎babol noshirvani university of technology‎, ‎babol‎, ‎mazandaran‎, ‎iran.

in this paper, operational matrices of riemann-liouville fractional integration and caputo fractional differentiation for shifted jacobi polynomials are considered. using the given initial conditions, we transform the fractional differential equation (fde) into a modified fractional differential equation with zero initial conditions. next, all the existing functions in modified differential equ...

فتحعلیان, فریده , نوری امامزاده‌ئی, محمدرضا ,

Soil and water resources are limited and optimal use of water resources in agriculture requires accurate determination of water consumed by plant species in different circumstances. This situation is necessary more than ever due to fast development of greenhouse cultivation. In this regard, to determine evapotranspiration and crop coefficient (KC) of greenhouse cucumber, two microlysimeters wer...

Journal: :مدیریت آب و آبیاری 0
امیر احمد دهقانی استادیار گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان محمد قبائی سوق دانشجوی کارشناسی ارشد مهندسی منابع آب، گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان حسین شریفان استادیار گروه مهندسی آب، گروه مهندسی آب، دانشگاه علوم کشاورزی و منابع طبیعی گرگان نوید دهقانی دانشجوی کارشناسی ارشد مهندسی آبخیزداری، گروه مهندسی آبخیزداری، دانشکده منابع طبیعی و علوم دریایی، دانشگاه تربیت مدرس

accurate estimation of reference evapotranspiration plays a key role in water resources management and irrigation scheduling. the fao penman-monteith (f-p-m) is a reference method for calculation of evapotranspiration that needs temperature, humidity, wind speed and solar radiation. in many stations, it is not an easy task to measure the whole weather variables. thus, in this situation, one mus...

Journal: :J. Sci. Comput. 2011
Jehanzeb Hameed Chaudhry Stephen D. Bond Luke N. Olson

The inclusion of steric effects is important when determining the electrostatic potential near a solute surface. We consider a modified form of the Poisson-Boltzmann equation, often called the Poisson-Bikerman equation, in order to model these effects. The modifications lead to bounded ionic concentration profiles and are consistent with the Poisson-Boltzmann equation in the limit of zero-size ...

In this paper, the fractional partial differential equations are defined by modified Riemann-Liouville fractional derivative. With the help of fractional derivative and fractional complex transform, these equations can be converted into the nonlinear ordinary differential equations. By using solitay wave ansatz method, we find exact analytical solutions of the space-time fractional Zakharov Kuz...

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