Performance of Recalibrated Equations for the Estimation of Daily Reference Evapotranspiration

Mallikarjuna, P.; Jyothy, S. Aruna; Murthy, D. S. Ramachandra; Reddy, K. Chandrasekhar

doi:10.1007/s11269-014-0733-9

Cited by 18 publications

(10 citation statements)

References 15 publications

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“…The performance of MLP and GFF models with accuracy over 90 % for all the periods and R 2 higher than 0.84 were better LR and PNN models. The MAE ranged 0.588-0.840 mm day −1 , and R 2 ranged from 0.60 to 0.82, which were both lower than R 2 of some previous studies (e. g. Traore et al 2010), while they still fall in the range of most studies (R 2 ranged from 0.6043 to 0.9995 in Kisi and Zounemat-Kermani (2014), 0.391 to 0.990 in Mallikarjuna et al (2014). The reason was that only Tmin and Tmax were used as inputs in this work, while some other weather variables, such as solar radiation, wind speed and relative humidity were also included as inputs in previous studies.…”

Section: Resultscontrasting

confidence: 56%

“…where x i is the temperature forecast or estimated/forecasted ET o ; y i is the observed temperature or calculated ET 0 ; i is the forecast sample sequence number; i=1,2,…n, x is the average forecast value of the sample sequence number; y is the average calculated value of the sample sequence number; and n is the sample number of the forecast value (Mallikarjuna et al 2014;Kisi and Zounemat-Kermani 2014).…”

Section: Discussionmentioning

confidence: 99%

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Medium Range Daily Reference Evapotranspiration Forecasting by Using ANN and Public Weather Forecasts

Luo

Traoré

Lyu

et al. 2015

Water Resour Manage

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Medium range daily reference evapotranspiration (ET o ) forecasts are very helpful for farmers or irrigation system operators for improving their irrigation scheduling. We tested four artificial neural networks (ANNs) for ET o forecasting using forecasted temperatures data retrieved from public weather forecasts. Daily meteorological data were collected to train and validate the ANNs against the Penman-Monteith (PM) model. And then, the temperature forecasts for 7-day ahead were entered into the validated ANNs to produce ET o forecast outputs. The forecasting performances of models were evaluated through comparisons between the ET o forecasted by ANNs and ET o calculated by PM from the observed meteorological data. The correlation coefficients between observed and forecasted temperatures for all stations were all greater than 0.91, and the accuracy of the minimum temperature forecast (error within ± 2°C) ranged from 68.34 to 91.61 %, whereas for the maximum temperature it ranged from 51.78 to 57.44 %. The accuracy of the ET o forecast (error within ± 1.5 mm day −1 ) ranged from 75.53 to 78.14 %, the average values of the mean absolute error ranged from 0.99 to 1.09 mm day −1 , the average values of the root mean square error ranged from 0.87 to 1.36 mm day −1 , and the average values of the correlation coefficient ranged from 0.70 to 0.75. Water Resour ManageThe results suggested that ANNs can be considered as a promising ET o forecasting tool. The forecasting performance can be improved by promoting temperature forecast accuracy.

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Section: Resultscontrasting

confidence: 56%

Section: Discussionmentioning

confidence: 99%

Medium Range Daily Reference Evapotranspiration Forecasting by Using ANN and Public Weather Forecasts

Luo

Traoré

Lyu

et al. 2015

Water Resour Manage

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“…where ET 0 is reference evapotranspiration (mm day À1 ), R n net radiation at the crop surface (MJ m À2 day À1 ), G soil heat flux density (MJ m À2 day À1 ), T mean daily air temperature at 2 m height (°C), u 2 wind speed at 2 m height (m s À1 ), e s saturation vapour pressure (kPa), e a actual vapour pressure (kPa), (e s À e a ) saturation vapour pressure deficit (kPa), D slope vapour pressure curve (kPa°C À1 ), Ç psychrometric constant (kPa°C À1 ) (Mallikarjuna et al, 2014).…”

Section: The Fao Penman-monteith Methodsmentioning

confidence: 99%

Effect of baseline meteorological data selection on hydrological modelling of climate change scenarios

Remesan

Holman

2015

Journal of Hydrology

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Keywords:Uncertainty TRMM3B42 V7 Aphrodite Impact response surface Evapotranspiration Climate change s u m m a r y This study evaluates how differences in hydrological model parameterisation resulting from the choice of gridded global precipitation data sets and reference evapotranspiration (ETo) equations affects simulated climate change impacts, using the north western Himalayan Beas river catchment as a case study. Six combinations of baseline precipitation data (the Tropical Rainfall Measuring Mission (TRMM) and the Asian Precipitation -Highly Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE)) and Reference Evapotranspiration equations of differing complexity and data requirements (Penman-Monteith, Hargreaves-Samani and Priestley-Taylor) were used in the calibration of the HySim model. Although the six validated hydrological models had similar historical model performance (Nash-Sutcliffe model efficiency coefficient (NSE) from 0.64 to 0.70), impact response surfaces derived using a scenario neutral approach demonstrated significant deviations in the models' responses to changes in future annual precipitation and temperature. For example, the change in Q10 varies between À6.5% and À11.5% in the driest and coolest climate change simulation and +79% to +118% in the wettest and hottest climate change simulation among the six models. The results demonstrate that the baseline meteorological data choices made in model construction significantly condition the magnitude of simulated hydrological impacts of climate change, with important implications for impact study design.

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“…ET 0 was calculated using the FPM equation (Allen et al, ), which is applicable to various regions of the world such as America (Tsanis et al, ; Exner‐Kittridge and Rains, ), Europe (Fermor et al, ; Gavin and Agnew, ), Africa (Schumacher et al, ; Farg et al, ), Asia (Mallikarjuna et al, ; Valipour, ) and Oceania (Chiew et al, ; Ortega‐Farias et al, ). The FPM specifies hypothetical reference values for plant height (0.12 m), fixed surface resistance (70 s m −1 ) and albedo (0.23):

{normalE normalT}_{0} = \frac{0.408 Δ ((), R_{n} - G) + γ \frac{900}{T + 273} u_{2} ((), e_{s} - e_{a})}{Δ + γ \cdot ((), 1 + 0.34 u_{2})}

…”

Section: Methodsmentioning

confidence: 99%

Spatiotemporal analysis of potential evapotranspiration in the Changwu tableland from 1957 to 2012

2015

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ABSTRACT:The Changwu tableland is located in the semi-humid to semi-arid transition area of the Loess Plateau, China. In the present study, the daily potential evapotranspiration (ET 0 ) of the Changwu tableland was calculated using the FAO Penman-Monteith (FPM) equation for the years 1957-2012, and the temporal variation and frequency distribution characteristics were analysed. The results indicate that the annual average ET 0 of the Changwu tableland was 949.3 mm, varying from 789.2 to 1093.3 mm; a slight downward trend with a rate of −0.48 mm year −1 was found. An abrupt increase occurred in 1994. The ET 0 values that correspond to frequencies of 5, 10, 25, 50, 75, 90 and 95% were 1076.8, 1047.6, 999.7, 947.8, 897.3, 853.0 and 827.0 mm, respectively. The recurrence intervals of maximum and minimum ET 0 were both more than 50 years. The contributions of T max , T min , vapour pressure, wind speed and sunshine hours to changes in ET 0 were 0.74, 0.07, −0.51, −0.57 and −0.23, respectively. The change in ET 0 and the meteorological factors in the Changwu tableland are worthy of attention; measures to reduce the negative impacts of climate change are necessary.

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Performance of Recalibrated Equations for the Estimation of Daily Reference Evapotranspiration

Cited by 18 publications

References 15 publications

Medium Range Daily Reference Evapotranspiration Forecasting by Using ANN and Public Weather Forecasts

Medium Range Daily Reference Evapotranspiration Forecasting by Using ANN and Public Weather Forecasts

Effect of baseline meteorological data selection on hydrological modelling of climate change scenarios

Spatiotemporal analysis of potential evapotranspiration in the Changwu tableland from 1957 to 2012

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