Sensitivity of the Food and Agriculture Organization Penman–Monteith Evapotranspiration Estimates to Alternative Procedures for Estimation of Parameters

Nandagiri, Lakshman; Kovoor, Gicy M.

doi:10.1061/(asce)0733-9437(2005)131:3(238)

Cited by 36 publications

(17 citation statements)

References 13 publications

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“…The results indicated that the model was unfit for use under temperate conditions when the original calibration coefficients were used. At 12 • 57 N latitude Nandagiri and Kovoor (2005) similarly found the model predictions had a high bias and scatter when the results were compared to Allen et al (1998). Irmak et al (2003) only tested the model at mid-latitude sites.…”

Section: Multiple Regression Modelsmentioning

confidence: 55%

Long-term comparisons of net radiation calculation schemes

Kjaersgaard

Cuenca

Plauborg³

et al. 2007

Boundary-Layer Meteorol

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Six commonly used models for calculating daily net radiation were tested against measured net radiation. Meteorological data from 32 and 7 consecutive years obtained at two temperate sites were used. The extensive duration of the datasets ensured that all weather conditions and extreme events were captured. A set of statistical procedures was used to evaluate the performance of the models. The mean bias errors ranged from 0.0 W m −2 to 24.8 W m −2 and 0.1-24.7 W m −2 and root mean square error from 11.0 W m −2 to 28.1 W m −2 and 10.0-27.9 W m −2 at the two sites respectively, for days without snow cover on the ground. The best agreement was found when locally calibrated model coefficients were used. Only negligible differences in model performances were found between the two sites and the differences were lower than the inaccuracies of the net radiation instruments used. Including days with snow cover in the analysis lead to a slight increase in the bias and scatter of the predictions. Model performances were in general better during summertime than wintertime. Altered albedo values during winter caused by generally low sun angles were likely the cause of this. Analysis showed that at least 5 years of data were needed to obtain stable calibration coefficients for local calibration of the models. Based on the results from this study, and due to their physical background, two physical based models were recommended for calculating daily values of net radiation under tem-418 Boundary-Layer Meteorol (2007) 123:417-431 perate climate regimes. A simple adjustment of the calibration coefficients based on climate regime was suggested for these models.

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Section: Multiple Regression Modelsmentioning

confidence: 55%

Long-term comparisons of net radiation calculation schemes

Kjaersgaard

Cuenca

Plauborg³

et al. 2007

Boundary-Layer Meteorol

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“…ET 0 was currently predicted by the HS equation, which is often preferred to other more complicated methods since it requires only maximum and minimum air temperatures and is reasonably accurate [48]. The ET 0 estimated by the HS equation have been compared to the ET 0 computed with the Penman-Monteith equation (PM-ET 0 ) equation [11], using full datasets, or to grass lysimeter data, indicating that the HS method performs well in most climatic regions, with the exception of humid areas [49][50][51][52]. The used version of the HS equation was suggested for Mediterranean coastal areas by [39], who recognized its superiority over other temperature methods in water limited ecosystems.…”

Section: Discussionmentioning

confidence: 99%

Integration of Ground and Multi-Resolution Satellite Data for Predicting the Water Balance of a Mediterranean Two-Layer Agro-Ecosystem

et al. 2016

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Abstract:The estimation of site water budget is important in Mediterranean areas, where it represents a crucial factor affecting the quantity and quality of traditional crop production. This is particularly the case for spatially fragmented, multi-layer agricultural ecosystems such as olive groves, which are traditional cultivations of the Mediterranean basin. The current paper aims at demonstrating the effectiveness of spatialized meteorological data and remote sensing techniques to estimate the actual evapotranspiration (ET A ) and the soil water content (SWC) of an olive orchard in Central Italy. The relatively small size of this orchard (about 0.1 ha) and its two-layer structure (i.e., olive trees and grasses) require the integration of remotely sensed data with different spatial and temporal resolutions (Terra-MODIS, Landsat 8-OLI and Ikonos). These data are used to drive a recently proposed water balance method (NDVI-Cws) and predict ET A and then site SWC, which are assessed through comparison with sap flow and soil wetness measurements taken in 2013. The results obtained indicate the importance of integrating satellite imageries having different spatio-temporal properties in order to properly characterize the examined olive orchard. More generally, the experimental evidences support the possibility of using widely available remotely sensed and ancillary datasets for the operational estimation of ET A and SWC in olive tree cultivation systems.

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“…The estimate for Δ using T a only is shown in Equation (11), which has been widely used to calculate λE in the PM method (Allen et al [30], Xu and Singh [33], Nandagiri and Kovoor [14], Donatelli et al [34], etc. ).…”

Section: The Penman-monteith Methods For Calculating Latent Heat Fluxmentioning

confidence: 99%

“…Many studies conducted sensitivity analyses on parameterization and appropriate adaptation of the PM method (Thom and Oliver [7], De Bruin and Holtslag [8], Shuttleworth and Wallace [9], Allen [10], Kustas et al [11], Moran et al [6], Alves and Pereira [12], Gavin and Agnew [13], Nandagiri and Kovoor [14], Allen et al [15], Gong et al [16], Zhao et al [17], etc.). Otles and Gutowski [18] studied atmospheric stability effects on the PM method and compared the evapotranspiration from PM to the Bowen-ratio and lysimeter data.…”

Section: Introductionmentioning

confidence: 99%

Comparison of Latent Heat Flux Using Aerodynamic Methods and Using the Penman–Monteith Method with Satellite-Based Surface Energy Balance

et al. 2014

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A surface energy balance was conducted to calculate the latent heat flux (λE) using aerodynamic methods and the Penman-Monteith (PM) method. Computations were based on gridded weather and Landsat satellite reflected and thermal data. The surface energy balance facilitated a comparison of impacts of different parameterizations and assumptions, while calculating λE over large areas through the use of remote sensing. The first part of the study compares the full aerodynamic method for estimating latent heat flux against the appropriately parameterized PM method with calculation of bulk surface resistance (r s ). The second part of the study compares the appropriately parameterized PM method against the PM method, with various relaxations on parameters. This study emphasizes the use of separate aerodynamic equations (latent heat flux and sensible heat flux) against the combined Penman-Monteith equation to calculate λE when surface temperature (T s ) is much warmer than air temperature (T a ), as will occur under water stressed conditions. The study was conducted in southern Idaho for a 1000-km 2 area over a range of land use classes and for two Landsat satellite overpass dates. The results show discrepancies in latent heat flux (λE) values when the PM method is used with simplifications and relaxations, compared to the appropriately parameterized PM method and full aerodynamic method. Errors were particularly significant in areas of sparse vegetation where differences between T s and T a were high. The maximum RMSD between the correct PM method and simplified PM methods was about 56 W/m 2 in sparsely vegetated sagebrush desert where the same surface resistance was applied.

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Sensitivity of the Food and Agriculture Organization Penman–Monteith Evapotranspiration Estimates to Alternative Procedures for Estimation of Parameters

Cited by 36 publications

References 13 publications

Long-term comparisons of net radiation calculation schemes

Long-term comparisons of net radiation calculation schemes

Integration of Ground and Multi-Resolution Satellite Data for Predicting the Water Balance of a Mediterranean Two-Layer Agro-Ecosystem

Comparison of Latent Heat Flux Using Aerodynamic Methods and Using the Penman–Monteith Method with Satellite-Based Surface Energy Balance

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