A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate
Abstract
:1. Introduction
2. Materials and Methods
2.1. Study Area
2.2. Evapotranspiration Estimation Methods
2.3. Evaluation Criteria
- The coefficients of regression and determination relating observed and simulated data, b and R2, respectively, are defined as:
- The root mean square error, RMSE, which characterizes the variance of the estimation error:
3. Results
3.1. Estimating a Monthly Adjusted Radiation Adjustment Coefficient for Each Location
3.2. Validation of a Maximum Temperature-Based ETo Estimation Procedure
3.3. Comparing the Accuracy of MaxTET and Monthly Adjusted Hargreaves–Samani Methods
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Weather Station | Code | Latitude (N) | Longitude (W) | Elevation (m) | Distance to the Sea (km) | Period | Tmax (°C) | Tmin (°C) | Eto (mm day−1) | Rainfall (mm year−1) |
---|---|---|---|---|---|---|---|---|---|---|
Aljustrel | Alj | 37°58′17″ | 08°11′25″ | 104 | 55 | 2001–2019 | 29.1 (±5.9) | 12.9 (±3.5) | 4.7 (±1.7) | 204 |
Alvalade do Sado | Alv | 37°55′44″ | 08°20′45″ | 79 | 40 | 2001–2019 | 29.2 (±5.9) | 13.3 (±3.3) | 4.8 (±1.7) | 183 |
Beja | Bej | 38°02′15″ | 07°53′06″ | 206 | 79 | 2001–2019 | 28.8 (±6.1) | 13.2 (±3.5) | 5.0 (±1.8) | 216 |
Castro Verde | CV | 37°45′20.5″ | 08°04′35.4″ | 200 | 64 | 2001–2019 | 29.0 (±6.1) | 12.8 (±3.5) | 5.3 (±2.0) | 151 |
Elvas | Elv | 38°54′56″ | 07°05′56″ | 202 | 160 | 2001–2019 | 29.9 (±6.5) | 13.0 (±4.0) | 4.9 (±1.8) | 218 |
Estremoz | Est | 38°52′20″ | 07°35′49″ | 404 | 120 | 2006–2019 | 27.5 (±6.4) | 12.2 (±3.7) | 4.2 (±1.5) | 256 |
Évora | Evo | 38°44′16″ | 07°56′10″ | 246 | 85 | 2002–2019 | 28.6 (±6.2) | 12.0 (±3.6) | 4.5 (±1.6) | 245 |
Ferreira do Alentejo | FdA | 38°02′42″ | 08°15′59″ | 74 | 47 | 2001–2019 | 29.3 (±5.8) | 12.8 (±3.5) | 4.5 (±1.6) | 210 |
Moura | Mou | 38°05′15″ | 07°16′39″ | 172 | 100 | 2001–2019 | 30.2 (±6.4) | 12.0 (±4.3) | 4.4 (±1.6) | 204 |
Odemira | Ode | 37°30′06″ | 08°45′12″ | 92 | 4 | 2002–2019 | 23.9 (±4.2) | 13.3 (±2.8) | 3.8 (±1.1) | 213 |
Redondo | Red | 38°31′41″ | 07°37′40″ | 236 | 105 | 2001–2019 | 29.3 (±6.4) | 13.6 (±3.7) | 5.1 (±1.9) | 210 |
Serpa | Ser | 37°58′06″ | 07°33′03″ | 190 | 90 | 2004–2019 | 30.3 (±6.4) | 13.6 (±3.6) | 4.8 (±1.7) | 197 |
Viana do Alentejo | Via | 38°21′39″ | 08°07′32″ | 138 | 57 | 2006–2019 | 28.4 (±6.1) | 12.6 (±3.4) | 4.8 (±1.7) | 247 |
Vidigueira | Vid | 38°10′36.8″ | 07°47′35.1″ | 155 | 86 | 2007–2019 | 29.9 (±6.3) | 13.2 (±3.6) | 4.8 (±1.7) | 178 |
Station | Month | Irrigation Season 1 | ||||||
---|---|---|---|---|---|---|---|---|
April | May | June | July | August | September | October | ||
Aljustrel | 0.15 | 0.15 | 0.15 | 0.16 | 0.16 | 0.15 | 0.16 | 0.16 |
Alvalade do Sado | 0.15 | 0.16 | 0.16 | 0.16 | 0.16 | 0.15 | 0.16 | 0.16 |
Beja | 0.16 | 0.17 | 0.17 | 0.17 | 0.17 | 0.17 | 0.18 | 0.17 |
Castro Verde | 0.16 | 0.17 | 0.17 | 0.18 | 0.18 | 0.17 | 0.19 | 0.17 |
Elvas | 0.15 | 0.15 | 0.15 | 0.16 | 0.16 | 0.15 | 0.16 | 0.16 |
Estremoz | 0.15 | 0.15 | 0.14 | 0.15 | 0.14 | 0.14 | 0.15 | 0.14 |
Évora | 0.14 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
Ferreira do Alentejo | 0.14 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
Moura | 0.13 | 0.13 | 0.13 | 0.14 | 0.14 | 0.14 | 0.14 | 0.14 |
Odemira | 0.17 | 0.17 | 0.16 | 0.16 | 0.16 | 0.17 | 0.17 | 0.17 |
Redondo | 0.16 | 0.16 | 0.16 | 0.17 | 0.17 | 0.17 | 0.19 | 0.17 |
Serpa | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 | 0.15 |
Viana do Alentejo | 0.15 | 0.15 | 0.15 | 0.16 | 0.16 | 0.16 | 0.18 | 0.16 |
Vidigueira | 0.15 | 0.16 | 0.15 | 0.15 | 0.15 | 0.14 | 0.16 | 0.15 |
Alentejo | 0.15 | 0.16 | 0.15 | 0.16 | 0.16 | 0.16 | 0.16 | 0.16 |
Station | Monthly Adjusted HS Method | Seasonal Adjusted HS Method | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
Calibration | Validation | All | ||||||||||
b | R2 | RMSE | b | R2 | RMSE | b | R2 | RMSE | b | R2 | RMSE | |
Aljustrel | 0.99 | 0.80 | 0.74 | 0.97 | 0.80 | 0.76 | 0.98 | 0.80 | 0.75 | 1.01 | 0.80 | 0.78 |
Alvalade do Sado | 0.99 | 0.81 | 0.73 | 0.98 | 0.84 | 0.68 | 0.98 | 0.82 | 0.71 | 0.99 | 0.82 | 0.71 |
Beja | 1.00 | 0.82 | 0.78 | 1.02 | 0.85 | 0.73 | 1.01 | 0.83 | 0.76 | 1.01 | 0.83 | 0.77 |
Castro Verde | 0.99 | 0.84 | 0.80 | 0.98 | 0.86 | 0.75 | 0.99 | 0.85 | 0.78 | 0.96 | 0.83 | 0.82 |
Elvas | 0.99 | 0.79 | 0.80 | 0.97 | 0.78 | 0.85 | 0.98 | 0.79 | 0.83 | 1.01 | 0.78 | 0.86 |
Estremoz | 1.00 | 0.81 | 0.64 | 0.99 | 0.78 | 0.73 | 0.99 | 0.79 | 0.69 | 0.96 | 0.79 | 0.70 |
Évora | 0.98 | 0.78 | 0.79 | 0.98 | 0.75 | 0.82 | 0.98 | 0.76 | 0.80 | 0.99 | 0.76 | 0.80 |
Ferreira do Alentejo | 1.01 | 0.79 | 0.74 | 1.00 | 0.81 | 0.69 | 1.00 | 0.80 | 0.71 | 1.01 | 0.80 | 0.72 |
Moura | 1.00 | 0.80 | 0.68 | 0.97 | 0.81 | 0.70 | 0.98 | 0.81 | 0.69 | 1.01 | 0.81 | 0.71 |
Odemira | 0.99 | 0.64 | 0.66 | 0.97 | 0.72 | 0.59 | 0.98 | 0.68 | 0.63 | 1.01 | 0.69 | 0.64 |
Redondo | 0.98 | 0.80 | 0.84 | 0.98 | 0.79 | 0.88 | 0.98 | 0.79 | 0.86 | 1.00 | 0.79 | 0.88 |
Serpa | 1.00 | 0.78 | 0.79 | 0.96 | 0.79 | 0.79 | 0.98 | 0.78 | 0.79 | 0.98 | 0.78 | 0.79 |
Viana do Alentejo | 0.98 | 0.83 | 0.69 | 0.96 | 0.82 | 0.76 | 0.97 | 0.83 | 0.73 | 0.99 | 0.81 | 0.77 |
Vidigueira | 0.99 | 0.80 | 0.74 | 0.97 | 0.79 | 0.78 | 0.98 | 0.80 | 0.75 | 0.97 | 0.80 | 0.75 |
Alentejo | 0.99 | 0.79 | 0.79 | 0.98 | 0.79 | 0.79 | 0.98 | 0.79 | 0.79 | 1.01 | 0.77 | 0.84 |
Station | Month | ||||||
---|---|---|---|---|---|---|---|
April | May | June | July | August | September | October | |
Aljustrel | 0.160 | 0.185 | 0.190 | 0.195 | 0.170 | 0.140 | 0.110 |
Alvalade do Sado | 0.165 | 0.190 | 0.195 | 0.195 | 0.175 | 0.140 | 0.115 |
Beja | 0.175 | 0.200 | 0.205 | 0.210 | 0.185 | 0.150 | 0.125 |
Castro Verde | 0.175 | 0.205 | 0.215 | 0.220 | 0.195 | 0.160 | 0.135 |
Elvas | 0.160 | 0.185 | 0.190 | 0.195 | 0.170 | 0.140 | 0.110 |
Estremoz | 0.160 | 0.175 | 0.175 | 0.180 | 0.155 | 0.125 | 0.105 |
Évora | 0.160 | 0.180 | 0.185 | 0.190 | 0.170 | 0.140 | 0.110 |
Ferreira do Alentejo | 0.155 | 0.180 | 0.180 | 0.180 | 0.160 | 0.130 | 0.110 |
Moura | 0.145 | 0.165 | 0.170 | 0.170 | 0.150 | 0.125 | 0.105 |
Odemira | 0.170 | 0.185 | 0.185 | 0.180 | 0.160 | 0.140 | 0.115 |
Redondo | 0.175 | 0.200 | 0.200 | 0.210 | 0.185 | 0.150 | 0.125 |
Serpa | 0.155 | 0.180 | 0.185 | 0.185 | 0.160 | 0.130 | 0.105 |
Viana | 0.160 | 0.185 | 0.185 | 0.195 | 0.180 | 0.145 | 0.130 |
Vidigueira | 0.160 | 0.185 | 0.185 | 0.190 | 0.165 | 0.130 | 0.110 |
Alentejo | 0.160 | 0.185 | 0.190 | 0.195 | 0.170 | 0.140 | 0.115 |
Station | Monthly Adjusted kTmax | ||||||||
---|---|---|---|---|---|---|---|---|---|
Calibration | Validation | All | |||||||
b | R2 | RMSE | b | R2 | RMSE | b | R2 | RMSE | |
Aljustrel | 1.00 | 0.78 | 0.79 | 0.98 | 0.78 | 0.81 | 0.99 | 0.78 | 0.80 |
Alvalade do Sado | 1.00 | 0.78 | 0.78 | 0.99 | 0.81 | 0.74 | 0.99 | 0.80 | 0.76 |
Beja | 1.00 | 0.79 | 0.85 | 1.02 | 0.82 | 0.80 | 1.01 | 0.81 | 0.82 |
Castro Verde | 1.00 | 0.80 | 0.92 | 0.99 | 0.82 | 0.84 | 0.99 | 0.81 | 0.88 |
Elvas | 1.00 | 0.78 | 0.84 | 0.98 | 0.76 | 0.88 | 0.99 | 0.77 | 0.86 |
Estremoz | 1.00 | 0.78 | 0.68 | 0.99 | 0.76 | 0.77 | 0.99 | 0.77 | 0.73 |
Évora | 1.00 | 0.76 | 0.82 | 1.00 | 0.73 | 0.85 | 1.00 | 0.75 | 0.84 |
Ferreira do Alentejo | 0.99 | 0.77 | 0.77 | 0.98 | 0.79 | 0.74 | 0.99 | 0.78 | 0.75 |
Moura | 1.00 | 0.79 | 0.69 | 0.97 | 0.80 | 0.72 | 0.98 | 0.79 | 0.71 |
Odemira | 1.00 | 0.63 | 0.67 | 0.97 | 0.68 | 0.63 | 0.99 | 0.65 | 0.65 |
Redondo | 1.00 | 0.78 | 0.89 | 0.99 | 0.77 | 0.93 | 1.00 | 0.78 | 0.91 |
Serpa | 1.00 | 0.76 | 0.82 | 0.96 | 0.77 | 0.84 | 0.98 | 0.76 | 0.83 |
Viana | 1.00 | 0.79 | 0.80 | 0.97 | 0.78 | 0.85 | 0.98 | 0.79 | 0.82 |
Vidigueira | 1.00 | 0.78 | 0.79 | 0.98 | 0.78 | 0.83 | 0.99 | 0.78 | 0.81 |
Alentejo | 0.99 | 0.77 | 0.83 | 0.97 | 0.77 | 0.83 | 0.98 | 0.77 | 0.83 |
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Rodrigues, G.C.; Braga, R.P. A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate. Sustainability 2021, 13, 349. https://doi.org/10.3390/su13010349
Rodrigues GC, Braga RP. A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate. Sustainability. 2021; 13(1):349. https://doi.org/10.3390/su13010349
Chicago/Turabian StyleRodrigues, Gonçalo C., and Ricardo P. Braga. 2021. "A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate" Sustainability 13, no. 1: 349. https://doi.org/10.3390/su13010349
APA StyleRodrigues, G. C., & Braga, R. P. (2021). A Simple Procedure to Estimate Reference Evapotranspiration during the Irrigation Season in a Hot-Summer Mediterranean Climate. Sustainability, 13(1), 349. https://doi.org/10.3390/su13010349