نتایج جستجو برای: evapotranspiration

تعداد نتایج: 6966  

Journal: :بوم شناسی کشاورزی 0
هدیه پوریزدان خواه تیمور رضوی پور محمدرضا خالدیان مجتبی رضایی

estimating and determining of rice water requirement, being the main cultivate of rasht region, is crucial for devoting water to this region. equations which are used to calculate the reference evapotranspiration (et0) are not match to all climatic conditions, due to their empirical bases. so, it is necessary to clarify proper methods for each region. crop coefficient (kc) is also the main para...

2014
Ibrahim Denka Kariyama

The potential of modeling the FAO Penman-Monteith (FAO-56 PM) method for computing reference crop evapotranspiration (ETo) using feed-forward backpropagation artificial neural networks (FFBANN) with minimal measured climate data such as with the air temperature (maximum and minimum) was investigated using local climatic data from the Wa Meteorological weather station. Three FFBANN models were d...

2015
Bing Gao Yue Qin Yuhan Wang Dawen Yang Yuanrun Zheng James M. Vose

The Heihe River is the second largest inland basin in China; runoff in the upper reach greatly affects the socio-economic development in the downstream area. The relationship between spatial vegetation patterns and catchment hydrological processes in the upper Heihe basin has remained unclear to date. In this study, a distributed ecohydrological model is developed to simulate the hydrological p...

Journal: :Proceedings. Mathematical, physical, and engineering sciences 2015
Xue Feng Amilcare Porporato Ignacio Rodriguez-Iturbe

The analysis of soil water partitioning in seasonally dry climates necessarily requires careful consideration of the periodic climatic forcing at the intra-annual timescale in addition to daily scale variabilities. Here, we introduce three new extensions to a stochastic soil moisture model which yields seasonal evolution of soil moisture and relevant hydrological fluxes. These approximations al...

2009
Luis C. de A. Lemos Filho Carlos R. de Mello Manoel A. de Faria Luiz G. de Carvalho

Scientific investigations about crop water requirements are of fundamental importance to the irrigation process. The main objective of this paper is to analyze and to map water requirements of coffee crop in Minas Gerais State, Brazil. Potential evapotranspiration values (ET0) were estimated by the Penman-Monteith-FAO method, using daily data sets available for 42 National Meteorology Institute...

2016
Shu Wang Hui Zheng Shuhua Liu Yucong Miao Jing Li

The wheat production in midland China is under serious threat by frequent Dry-Hot Wind (DHW) episodes with high temperature, low moisture and specific wind as well as intensive heat transfer and evapotranspiration. The numerical simulations of these episodes are important for monitoring grain yield and estimating agricultural water demand. However, uncertainties still remain despite that enormo...

2014
Yuei-An Liou

With the advent of new satellite technology, the radiative energy exchanges between Sun, Earth, and space may now be quantified accurately. Nevertheless, much less is known about the magnitude of the energy flows within the climate system and at the Earth’s surface, which cannot be directly measured by satellites. This review surveys the basic theories, observational methods, and different surf...

2017
Peng Zhao Johannes Lüers

Estimation of evapotranspiration plays an important role in understanding the water cycle on the earth, especially the water budget in agricultural ecosystems. The parameterization approach of the Penman-Monteith-Katerji-Perrier (PM-KP) model, accounting for the influence of meteorological variables and aerodynamic resistance on surface resistance, was proposed in the literature, but it has not...

Journal: :Remote Sensing 2010
Mireia Romaguera Arjen Y. Hoekstra Zhongbo Su Maarten S. Krol Mhd. Suhyb Salama

Remote sensing has long been a useful tool in global applications, since it provides physically-based, worldwide, and consistent spatial information. This paper discusses the potential of using these techniques in the research field of water management, particularly for ‘Water Footprint’ (WF) studies. The WF of a crop is defined as the volume of water consumed for its production, where green an...

2015
P. Karimi W. G. M. Bastiaanssen

The scarcity of water encourages scientists to develop new analytical tools to enhance water resource management. Water accounting and distributed hydrological models are examples of such tools. Water accounting needs accurate input data for adequate descriptions of water distribution and water depletion in river basins. Ground-based observatories are decreasing, and not generally accessible. R...

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