نتایج جستجو برای: reference evapotranspiration

تعداد نتایج: 277505  

The aim of this research is the study of the climate change impacts on the seasonal and annual reference evapotranspiration time scales in some selected stations located in the West of Iran. To this purpose, four stations including Sanandaj, Saghez, Khorramabad and Kermanshah synoptic stations with enough long-term data were selected and the climate change impact on the reference evapotranspira...

اسلامیان, سید سعید , زارعیان, محمدجواد, عابدی کوپایی, جهانگیر ,

Abstract Knowing crop evapotranspiration at any time is very important in management of irrigation systems for greenhouse. Changes in evapotranspiration during the crop growth period are described by crop coefficient (Kc), which is defined as the ratio between crop evapotranspiration and reference evapotranspiration. This study was conducted to determine the evapotranspiration of cucumber, tom...

2014
Wei-guang Wang Shan Zou Zhao-hui Luo Wei Zhang Dan Chen Jun Kong

Evapotranspiration is one of the most important hydrological variables in the context of water resources management. An attempt was made to understand and predict the dynamics of reference evapotranspiration from a nonlinear dynamical perspective in this study. The reference evapotranspiration data was calculated using the FAO Penman-Monteith equation with the observed daily meteorological data...

Journal: :آب و خاک 0
موسوی بایگی موسوی بایگی عرفانیان عرفانیان سرمد سرمد

abstract one of the losses decrease's ways in fields, is the proper irrigation management, which its base is the accurate estimation of crop water requirement. equations which are used to calculate the reference evapotranspiration (eto), do not use the same climatic parameters and due to their empirical base, are not match to all climatic situations. so it is needed to clarify proper methods fo...

Journal: :اکو هیدرولوژی 0
معصومه نجفی دانشجوی کارشناسی ارشد، گروه مهندسی آب، دانشکدۀ کشاورزی، دانشگاه صنعتی اصفهان، اصفهان وحید عظیمی دانشجوی سابق مهندسی آب، گروه مهندسی آب، دانشکدۀ کشاورزی، دانشگاه تبریز، تبریز محمد شایان نژاد دانشیار گروه مهندسی آب، دانشکدۀ کشاورزی، دانشگاه صنعتی اصفهان، اصفهان

in this study, climatic parameters are used to evaluate the sensitivity of reference evapotranspiration in isfahan and rasht with two semi-arid and moderate climates using two intelligent methods during 1970-2010. in this research, multi-layer precpetron e (mlp) and gene expression programming (gep) intelligent models are used in order to analyze the sensitivity of reference evapotranspiration ...

Journal: :آب و خاک 0
حمید زارع ابیانه مریم بیات ورکشی صفر معروفی رضا امیری چایجان

abstract the present study is attempted to present the minimum required meteorological parameters for reference evapotranspiration estimation at hamedan region of iran from 1997 to 1998. employing pierson test, six meteorological parameters which are used by penman-montieth fao-56 method including maximum and minimum air temperature, maximum and minimum relative humidity, wind speed and daily s...

2004
Raj Vir Singh

Wheat is an important crop of India. Precise estimates of evapotranspiration can be obtained by multiplying crop coefficients to reference evapotranspiration using readily available climatic data. PenmanMonteith equation is adopted world wide as the most reliable and accurate method for computing reference evapotranspiration. The Food and Agriculture Organization (FAO) presented crop coefficien...

Ali Assareh, Hadis Davoodi

In order to determine the required water for irrigation it is necessary to calculate the amount of needed water by plant or evapotranspiration. The equations that are used to calculate evapotranspiration are not applying the same climatic parameters and, due to their experimental nature, they are not suitable for all climatic conditions. In the present study in order to compare evapotranspirati...

2015
Daniel J. Howes Paul H. Hutton

Restoration activities in the Central Valley of California and elsewhere require accurate evapotranspiration information, which can then be used for a wide variety of surface and subsurface hydrologic evaluations. However, directly measuring evapotranspiration can be difficult or impossible depending on the evaluation’s time frame. Transferability of measured evapotranspiration in time and spac...

The phenomenon of evapotranspiration causes water and moisture losses from water, soil and vegetation levels. Due to the small amount of atmospheric precipitation and water resource constraints in Iran, it is important to calculate it through a suitable method. The present research attempts to evaluate the evapotranspiration reference crop (ETo) and present it in the form of zoning map as a bas...

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