As a key hydrological parameter, daily reference evapotranspiration (ETo) determines the accuracy of the hydrological number of the crop, and, consequently, the regional optimization disposition of water resources. At present, the main methods for ETo estimation are the Penman-Monteith (PM) equation and its modified formula, both of which are based on climatic factors such as temperature, radia...

evaporation is a fundamental parameter in the hydrological cycle. this study examines the performance of m5model tree and artificial neural network (ann) models in estimating potential evapotranspiration calculated bypenman- monteith and hargreaves- samani equations. daily weather data from two meteorological stations in asemi-arid climate of iran, namely kerman and zahedan, were collected duri...

an accurate determination of evapotranspiration is required for many studies that involve estimation of the water balance. one methodology is the use of lysimeters. considering the semiarid climate of kerman province, in southeastern parts of iran, the only operating electronic weighing lysimeter in the country was used for calculating daily eto from april 2004 to march 2005 in three different ...

A climate model must include an accurate surface physics scheme in order to examine the interactions between the land and atmosphere. Given an increase in the surface radiative forcing, the sensitivity of latent heat flux to available energy plays an important role in determining the energy budget and has a significant impact on the response of surface temperature. The Penman–Monteith equation ...

The information on transpiration is vital for sustaining fragile ecosystem in arid/semiarid environment, including the Horqin Sandy Land (HSL) located in northeast China. However, such information is scarce in existing literature. The objectives of this study were to: (1) measure sap flow of selected individual stems of two sand-fixing plants, namely Salix gordejevii and Caragana microphylla, i...

Hidrolik tasarım süreci ve tarımsal sulama yönetiminde evapotranspirasyonun tahmini oldukça önemlidir. Bu çalışmada günlük evapotranspirasyon miktarı için ortalama sıcaklık (S), bağıl nem (N), rüzgâr hızı (R), solar radyasyon (SR) parametreleri kullanılmıştır. Penman-Monteith, FAO (Food and Agriculture Organization) tarafından önerilen standart bir metottur. metoda göre yapılmış (ET0), referans...

In both Australia and Swaziland large areas of sugarcane rely on irrigation to produce a viable crop or to improve rainfed productivity. Matching water supply to crop demand is essential for productivity and sustainability in any irrigation scheme. Historically Class-A pan evaporation was used as a basis for determining sugarcane water demand or evapotranspiration (ETc). ETc is now frequently o...

For the Penman±Monteith equation to be used to predict crop evapotranspiration in a one-step approach, methodologies for determining surface resistance (rs) must be available. One usual approach to the modelling of rs is to compute it by inverting the Penman±Monteith equation and then relate it to the most important environmental variables (radiation, temperature, vapour pressure deficit) using...