نتایج جستجو برای: hargreaves samani

تعداد نتایج: 589  

Journal: :Sustainability 2021

The Food and Agricultural Organization of the United Nations (FAO) Penman–Monteith (PM) method is widely regarded as most effective reference evapotranspiration (ETo) estimator; however, it requires a wide range data that may be scarce in some rural regions. When feasible relative humidity, solar radiation wind speed are unavailable, temperature-based useful to estimate ETo provide suitable sup...

2017
Candida F Dewes Imtiaz Rangwala Joseph J Barsugli Michael T Hobbins Sanjiv Kumar

Several studies have projected increases in drought severity, extent and duration in many parts of the world under climate change. We examine sources of uncertainty arising from the methodological choices for the assessment of future drought risk in the continental US (CONUS). One such uncertainty is in the climate models' expression of evaporative demand (E0), which is not a direct climate mod...

Journal: :Çukurova Üniversitesi Mühendislik Fakültesi Dergisi 2022

Suyun öneminin tartışılmaz olduğu gerçeğini göz önüne alarak, hidrolojik çevrimin ve onun en karmaşık bileşenlerinden biri olan evapotranspirasyon (ET) kaybının iyi belirlenmesi gerekmektedir. Topraktan açık su yüzeylerinden buharlaşma bitkilerden terleme yoluyla kaybedilen suyun birleşimi olarak tanımlanan ET değerini belirlemek amacıyla birçok ampirik yöntem geliştirilmiş bu yöntemler üzerind...

Journal: :Agriculture 2022

Accurately estimating and forecasting evapotranspiration is one of the most important tasks to strengthen water resource management, especially in desert areas such as La Yarada, Tacna, Peru, a region located at head Atacama Desert. In this study, we used temperature, humidity, wind speed, air pressure, solar radiation from local weather station forecast potential (ETo) using machine learning. ...

Journal: :International Journal of Climatology 2021

This study analyses long-term changes in drought indices (Standardised Precipitation Index—SPI, Standardised Precipitation–Evapotranspiration Index—SPEI) at 1 and 3 months scales 182 stations 11 central eastern European countries during 1949–2018. For comparative purposes, the necessary atmospheric evaporative demand (AED) to obtain SPEI was calculated using two methods, Hargreaves-Samani (SPEI...

2016
Devendra M. Amatya Charles A. Harrison

Studies examining potential evapotranspiration (PET) for a mature forest reference compared with standard grass are limited in the current literature. Data from three long-term weather stations located within 10 km of each other in the USDA Forest Service Santee Experimental Forest (SEF) in coastal South Carolina were used to (1) evaluate monthly and annual PET estimates from five different met...

Journal: :اکو هیدرولوژی 0
رستا نظری کارشناس‏ارشد رشتۀ آبیاری و زهکشی، گروه مهندسی آب دانشگاه بین‏المللی امام خمینی(ره) عباس کاویانی استادیار گروه مهندسی آب دانشگاه بین‏المللی امام خمینی(ره)

iran was located in the arid belt and desert region of the world. this climatic situation was presented in several parts of iran such as qazvin. evapotranspiration is one the most important parameter which was effect on agricultural development. there are different methods for estimating this item which selected by climatic conditions. this research concentrates to evaluate 28 empirical and com...

Journal: :Italian journal of agrometeorology 2022

Accurate estimation of reference evapotranspiration is essential for agricultural management and water resources engineering applications. In the present study, ability precision three artificial intelligence (AI) models (i.e., Support Vector Machines (SVMs), Adaptive Neuro-Fuzzy Inference System (ANFIS) Categorical Boosting (CatBoost)) were assessed estimating daily (ET0) using limited weather...

مدل­های زیادی بر مبنای گروه­های رطوبتی، تشعشعی، دمایی و ترکیبی در برآورد تبخیرتعرق وجود دارد. هدف اصلی این تحقیق کالیبراسیون روش­های تبخیرتعرق و انتخاب بهترین روش، تحت شرایط اقلیمی متفاوت در استان­های ایران است. در این تحقیق، اقدام به جمع­­آوری داده­های هواشناسی از 10 ایستگاه سینوپتیک در استان­های ایران شده است و در مقایسه­ای که بین نتایج  تبخیرتعرق محاسبه شده بر مبنای چهار گروه تجربی موجود و د...

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