Evaluation of models for estimating the reference evapotranspiration in Colombian Coffee Zone

• Main Authors: Ramírez Víctor Hugo, Mejía Alexandra, Marín Elsa Viviana, Arango Rafael
• Format: Article
• Language: English
• Published: Centro Editorial of Facultad de Ciencias Agrarias, Universidad Nacional de Colombia 2011-04-01
• Series: Agronomía Colombiana
• Online Access: http://www.revistas.unal.edu.co/index.php/agrocol/article/view/28641

<p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">The reference evapotranspiration (ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">) is an important variable for hydrological studies, crop water requirements estimations, climatic zonification and water resources management. The FAO recommends the </span><em><span style="font-family: ";MinionPro-It";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-It; mso-ansi-language: EN-US;" lang="EN-US">Penman-Monteith </span></em><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">(P-M) and/or the </span><em><span style="font-family: ";MinionPro-It";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-It; mso-ansi-language: EN-US;" lang="EN-US">Hargreaves</span></em><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"> models as the worldwide useful for the ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o </span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">calculation.</span></p><p class="MsoNormal" style="text-align: justify; line-height: normal; margin: 0cm 0cm 0pt; mso-layout-grid-align: none;"><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">The objective of this work was to test the performance of these models in one place of the Colombian Coffee Belt, and identify limitations and proposes modifications. The ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o </span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">calculation were compared with daily lysimeter measurements. The principal disadvantages of the P-M model were: the lack of calibrated coefficient for the long wave radiation estimation (R</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">nl</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">) which affected seriously the net radiation estimation and finally the ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">, highly sensitivity at the wind speed changes, that make it inappropriate for locations without this data. The </span><em><span style="font-family: ";MinionPro-It";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-It; mso-ansi-language: EN-US;" lang="EN-US">Hargreaves</span></em><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US"> model, as FAO proposed, overestimate the ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">, which made necessary a modification. The ET</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">o </span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">estimation for this location was most sensible to atmospheric vapour and air temperature than the available energy in the atmosphere (R</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 5.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">n</span><span style="font-family: ";MinionPro-Regular";,";serif";; font-size: 9.5pt; mso-bidi-font-family: MinionPro-Regular; mso-ansi-language: EN-US;" lang="EN-US">-G).</span></p>