نتایج جستجو برای: modified penman equation

تعداد نتایج: 472208  

Journal: :آب و خاک 0
بختیاری بختیاری خلیلی خلیلی لیاقت لیاقت خانجانی خانجانی

abstract in recent years, automatic weather stations have been widely used for recording meteorological data in different time scales. therefore the accurate estimation of eto by combination equations can be evaluated using these set of short time scales data. daily eto can also be calculated by summation of hourly eto values. the purpose of this study is to compare the eto values estimated by ...

2011
Zhifang Chen Jinglei Wang Jingsheng Sun Aiwang Duan Zugui Liu Ni Song Xiaofei Liu

To improve the management of irrigation district is a key to develop water-saving agriculture. Based on the basic principles of water-saving irrigation, and using the method of Modified Penman Monteith and water balance equation, The system of irrigation management and decision support based on WEBGIS was developed,which is according to the soil moisture, crop growth status, meteorology change ...

ژورنال: علوم آب و خاک 2007
شاهرخ زندپارسا, , علیرضا سپاسخواه, , ابوالفضل مجنونی هریس, , علی اکبر کامگار حقیقی, ,

Optimal crop water requirement is needed for precise irrigation scheduling. Prediction of crop water requirements is a basic factor to achieve this goal. In this study, maize potential evapotranspiration (ETp) was prediced by maize simulation model (MSM). Then, it was evaluated and validated using experimental field data obtained in Agricultural Research Station of Shiraz University (Bajghah, F...

2006
M. A. Rawlins S. Frolking R. B. Lammers C. J. Vörösmarty

Hydrological models require accurate precipitation and air temperature inputs in order to adequately depict water fluxes and storages across Arctic regions. Biases such as gauge undercatch, as well as uncertainties in numerical weather prediction reanalysis data that propagate through water budget models, limit the ability to accurately model the terrestrial arctic water cycle. A hydrological m...

Journal: :Global change biology 2014
Ville Kasurinen Knut Alfredsen Pasi Kolari Ivan Mammarella Pavel Alekseychik Janne Rinne Timo Vesala Pierre Bernier Julia Boike Moritz Langer Luca Belelli Marchesini Ko van Huissteden Han Dolman Torsten Sachs Takeshi Ohta Andrej Varlagin Adrian Rocha Altaf Arain Walter Oechel Magnus Lund Achim Grelle Anders Lindroth Andy Black Mika Aurela Tuomas Laurila Annalea Lohila Frank Berninger

In this study latent heat flux (λE) measurements made at 65 boreal and arctic eddy-covariance (EC) sites were analyses by using the Penman-Monteith equation. Sites were stratified into nine different ecosystem types: harvested and burnt forest areas, pine forests, spruce or fir forests, Douglas-fir forests, broadleaf deciduous forests, larch forests, wetlands, tundra and natural grasslands. The...

2008
M. Weiß L. Menzel

This study compares four different potential evapotranspiration equations according to Priestley Taylor, Kimberly Penman, Penman Monteith (FAO-56) and Hargreaves on a global basis to demonstrate their difference, and assess their impact on the calculation of stream flows. The various equations of potential evapotranspiration show great differences in magnitude. But due to the limited availabili...

2012
Rhys Whitley Belinda Medlyn Melanie Zeppel Catriona Macinnis-Ng Derek Eamus

17 18 The responses of canopy conductance to variation in solar radiation, vapour pressure deficit and soil 19 moisture have been extensively modelled using a Jarvis-Stewart (JS) model. Modelled canopy 20 conductance has then often been used to predict transpiration using the Penman-Monteith (PM) 21 model. We previously suggested an alternative approach in which the JS model is modified to 22

Journal: :desert 2014
nozar ghahreman mahsa sameti

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...

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