Resumen

RAMIREZ, Víctor Hugo; MEJIA, Alexandra; MARIN, Elsa Viviana  y  ARANGO, Rafael. Evaluación de modelos para calcular la evapotranspiración de referencia en la zona cafetera de Colombia. Agron. colomb. [online]. 2011, vol.29, n.1, pp.107-114. ISSN 0120-9965.

The reference evapotranspiration (ET_o) is an important variable for hydrological studies, crop water requirements estimations, climatic zonification and water resources management. The FAO recommends the Penman-Monteith (P-M) and/or the Hargreaves models as the worldwide useful for the ET_o calculation. 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_o 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_nl) which affected seriously the net radiation estimation and finally the ET_o, highly sensitivity at the wind speed changes, that make it inappropriate for locations without this data. The Hargreaves model, as FAO proposed, overestimate the ETo, which made necessary a modification. The ET_o estimation for this location was most sensible to atmospheric vapour and air temperature than the available energy in the atmosphere (R_n-G).

Palabras clave : evapotranspiración; humedad atmosférica; radiación; temperatura; Penman-Monteith; Hargreaves; García and López; lisímetro.

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