Sensitivity Analysis of FAO-56 Penman-Monteith Method for Different Agro-ecological Regions of India

Debnath, Subhankar; Adamala, Sirisha; Raghuwanshi, N. S.

doi:10.1007/s40710-015-0107-1

Cited by 44 publications

(25 citation statements)

References 28 publications

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“…The sensitivity analysis showed u 2 and T m to be superior in estimating ET c in hyper-arid environments. This is consistent with the results of a study conducted by Debnath et al (2015). Other parameters also had an insignificant influence on ET c .…”

Section: Calibrated Models Validationsupporting

confidence: 92%

Evaluating and Calibrating Reference Evapotranspiration Models Using Water Balance under Hyper-Arid Environment

Mattar

Alazba

Alblewi

et al. 2016

Water Resour Manage

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This research investigates five reference evapotranspiration models (one combined model, one temperature-based model, and three radiation-based models) under hyper-arid environmental conditions at the operational field level. These models were evaluated and calibrated using the weekly water balance of alfalfa by EnviroSCAN to calculate crop evapotranspiration (ET c ). Calibration models were evaluated and validated using wheat and potatoes, respectively, on the basis of weekly water balance. Based on the results and discussion, the FAO-56 Penman-Monteith model proved to be superior in estimating ET c with a slight underestimation of 2 %. Meanwhile, the Hargreaves-Samani (HS) model (temperaturebased) underestimated ET c by 20 % and the Priestley-Taylor (PT) and Makkink (MK) models (radiation-based) had similar performances underestimating by up to 35 % of the measured ET c . The Turc (TR) model had the lowest performance compared with other models, demonstrating values underestimated by up to 60 % of the measured ET c . Local calibration based on alfalfa evapotranspiration measurements was used to rectify these underestimations. The surprisingly good performance of the calibrated simple HS model, with a new coefficient 0.0029, demonstrated its favorable potential to improve irrigation scheduling. The MK and PT models were in third and fourth rank, respectively, reflecting minor differences between one another. The new coefficients obtained for the MK and PT models were 1.99 and 0.963, Water Resour Manage respectively. One important observation was that the calibrated TR model performed poorly, with an increase in its coefficient from 0.013 to 0.034 to account for hyper-arid environmental conditions; moreover, it required additional seasonal calibration to adequately improve its performance.

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Section: Calibrated Models Validationsupporting

confidence: 92%

Evaluating and Calibrating Reference Evapotranspiration Models Using Water Balance under Hyper-Arid Environment

Mattar

Alazba

Alblewi

et al. 2016

Water Resour Manage

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“…In the context of climate change, there is much uncertainty regarding the changes in ET 0 and actual ET as a result of the complex nonlinear relationship between ET and climatic factors. There are large differences among the results obtained in studies that investigated the effects of climatic factors on ET (Debnath et al, ; Estévez et al, ; Nouri et al, ). In China, in terms of ET 0 studies, Wang et al () indicated that a change in wind speed was the main cause of the decrease of ET 0 from 1961 to 2013, followed by the changes in daily maximum temperature (T max ) and sunshine hours.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Changes in Reference Evapotranspiration, Pan Evaporation, and Actual Evapotranspiration and Their Influencing Factors in the North China Plain During 1998–2005

Liu

Chen

Pan

2019

Earth and Space Science

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Evapotranspiration (ET) plays an important role in both energy and water balances. Determining changes in the different types of ET and their influencing factors under climate change is crucial to fully understand the mechanisms controlling ET and regional water cycles. Based on ET and meteorological data measured during 1998–2005 at the Yucheng Comprehensive Experimental Station of the Chinese Academy of Sciences, the variation of reference ET (ET0), pan evaporation (Epan), and lysimeter ET (the actual ET, Elys) were estimated. Together with a Mann‐Kendall trend test, correlation and sensitivity analyses were conducted to determine the effects of climatic factors, crop coefficients (Kc), and leaf area index (LAI) on different types of ET. During 1998–2005, precipitation presented an upward trend at all time scales, and average temperature (Ta), minimum temperature (Tmin), relative humidity, Epan, and ET0 exhibited downward trends. Elys displayed a downward trend at the daily scale and an upward trend at monthly and annual scales. The correlation analysis indicated that Epan and Elys were significantly positively correlated with all climatic factors except precipitation and relative humidity. The sensitivity analysis revealed that except for relative humidity, the influence of the other climatic factors on ET0 was positive. The highest sensitivity was found for relative humidity, followed by Ta, maximum temperature (Tmax), and Tmin. An analysis of the influence of Kc and LAI on the actual ET indicated that with an increase of Kc and LAI, the actual water demand of crops also displayed an upward trend.

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“…The use of reanalysis data would enable the calculation of PET through the more accurate combined methods (such as PM). However, the uncertainties associated with reanalysis data should be carefully examined, as some of the modelled variables can display large errors (Reichler and Kim, 2008), and PM has also shown sensitivity to input data inaccuracy (Oudin et al, 2005;Debnath et al, 2015;Estévez et al, 2009;Gong et al, 2006).…”

Section: Further Findings and Future Workmentioning

confidence: 99%

Historical gridded reconstruction of potential evapotranspiration for the UK

Tanguy

Prudhomme

Smith

et al. 2018

Earth Syst. Sci. Data

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Abstract. Potential evapotranspiration (PET) is a necessary input data for most hydrological models and is often needed at a daily time step. An accurate estimation of PET requires many input climate variables which are, in most cases, not available prior to the 1960s for the UK, nor indeed most parts of the world. Therefore, when applying hydrological models to earlier periods, modellers have to rely on PET estimations derived from simplified methods. Given that only monthly observed temperature data is readily available for the late 19th and early 20th century at a national scale for the UK, the objective of this work was to derive the best possible UK-wide gridded PET dataset from the limited data available.To that end, firstly, a combination of (i) seven temperature-based PET equations, (ii) four different calibration approaches and (iii) seven input temperature data were evaluated. For this evaluation, a gridded daily PET product based on the physically based Penman-Monteith equation (the CHESS PET dataset) was used, the rationale being that this provides a reliable "ground truth" PET dataset for evaluation purposes, given that no directly observed, distributed PET datasets exist. The performance of the models was also compared to a "naïve method", which is defined as the simplest possible estimation of PET in the absence of any available climate data. The "naïve method" used in this study is the CHESS PET daily long-term average (the period from 1961 to 1990 was chosen), or CHESS-PET daily climatology.The analysis revealed that the type of calibration and the input temperature dataset had only a minor effect on the accuracy of the PET estimations at catchment scale. From the seven equations tested, only the calibrated version of the McGuinness-Bordne equation was able to outperform the "naïve method" and was therefore used to derive the gridded, reconstructed dataset. The equation was calibrated using 43 catchments across Great Britain.The dataset produced is a 5 km gridded PET dataset for the period 1891 to 2015, using the Met Office 5 km monthly gridded temperature data available for that time period as input data for the PET equation. The dataset includes daily and monthly PET grids and is complemented with a suite of mapped performance metrics to help users assess the quality of the data spatially.This dataset is expected to be particularly valuable as input to hydrological models for any catchment in the UK.The data can be accessed at https://doi.org/10.5285/17b9c4f7-1c30-4b6f-b2fe-f7780159939c.Published by Copernicus Publications.

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Sensitivity Analysis of FAO-56 Penman-Monteith Method for Different Agro-ecological Regions of India

Cited by 44 publications

References 28 publications

Evaluating and Calibrating Reference Evapotranspiration Models Using Water Balance under Hyper-Arid Environment

Evaluating and Calibrating Reference Evapotranspiration Models Using Water Balance under Hyper-Arid Environment

Analysis of Changes in Reference Evapotranspiration, Pan Evaporation, and Actual Evapotranspiration and Their Influencing Factors in the North China Plain During 1998–2005

Historical gridded reconstruction of potential evapotranspiration for the UK

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