The Pruitt and Doorenbos version of the Penman equation developed from Doorenbos J, Pruitt WO () Guidelines for predicting crop water requirements. Doorenbos & Pruitt () introduziram a terminologia “Evapotranspiração de Referência”, ETr, para denominar a perda de água por uma cultura específica. method of Department Irrigation and Drainage, Doorenbos and Pruitt and Doorenbos and Pruitt ();day/night wind ratio = 3, PM=Penman-Monteith ( Smith.

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In addition to the sensor readings Rnmeasuredfive different models were used in order to obtain the Rnestimated.

The use of an arbitrary and constant Kp 0. The objective of this study was to assess the accuracy of estimating evapotranspiration ET using the FAO Penman-Monteith FAOPM model, with measured and estimated net radiation Rnmeasured and Rnestimated, respectivelythe latter obtained via five different models.

Catalogue Persistent Identifier https: The Rnestimated obtained with the fifth model has a relatively high error. S pbk Main Reading Room – Most pre held offsite.

Subsequently, Pereira et al. Statistics for the evaluation and comparison of models. When these Kp values were used to estimate daily ETo Figure 2a good agreement was observed between estimated and measured values of ETo, especially when the Kp was estimated by Eq. Agricultural and Forest Meteorology, Amsterdam, v. We will contact you if necessary.


Equation for evaporation pan to evapotranspiration conversion. Based on the above discussion, the objective of this paper was to evaluate different methods used to predict Kp values and their influence on the daily estimates of ETo. The atmospheric pressure was determined by aneroid barograph, and sunshine duration was quantified with a Campbell-Stokes recorder. The use of a constant value of Kp showed to be a simple and practical option to convert ECA into ETo, however, this value must be calibrated and tested for different climatic conditions.

However, with modern automatic weather stations and computer facilities, it is convenient to automate ECA to ETo conversions using equations Snyder, How to cite this article.

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Food and Agriculture Organization of the United Nations. Revista Brasileira de Agrometeorologia, Santa Maria, v. Includes bibliographical references p.

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Class A pan coefficients (Kp) to estimate daily reference evapotranspiration (ETo)

Doorenbos fixed value is a practical and simple option to convert ECA into ETo, but this value must be pruitf for each place under different climatic conditions. The fifth was a linear regression model based on Rs.

The best ETo estimates were obtained when Kp values obtained by the Pereira’s and Cuenca’s methods were used. Table 2 presents the statistical analysis of ETo estimates using different Kp methods. Report on eoorenbos consultation on procedures for revision of FAO methodologies for crop water requirements. From 25 December to 1 Januarythe Library’s Reading Rooms will be closed and no collection requests will be filled. Reference evapotranspiration based on Class A pan evaporation.


However, the R 2 values, which indicate the precision of the estimates, varied between 0. According to Pereira et al. The following data were collected: New search User lists Site feedback Ask a librarian Help. The class A pan coefficient Kp has been used to convert pan evaporation ECA to grass-reference evapotranspiration EToan 1797 component in water management of irrigated crops.

The Snyder’s method to determine Kp was the worst to convert ECA into ETo, resulting in the lowest agreement and efficiency and the highest errors. Order a copy Copyright or permission restrictions may apply.

Cite this Email this Add to favourites Print this page. Advanced search Search history. Scientific Research An Academic Publisher. Four of those dooreenbos consider the effects of cloud cover: This fixed value is a simple and practical option to convert ECA in ETo, without the need of weather data as wind speed, relative humidity and temperature. Browse titles authors subjects uniform titles series callnumbers dewey numbers starting from optional.