Avaliação da eficácia do lisímetro de lençol freático constante, do tanque classe A e do modelo de Penmam-Monteith (FAO) para estimativa da evapotranspiração de referência (ETo)

• Autor(a) principal: Amorim, Marcelo Cid de
• Data de Publicação: 1997
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5269
• topic: Lisímetro; Lençol freático; Evapotranspiração; Meteorologia agrícola; Lysimeter; Groundwater; Evapotranspiration; Agricultural meteorology; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA

A field research work was carried out to evaluate the FAO Penman- Monteith method, the constant watertable lysimeter and the Class A pan for estimating the reference evapotranspiration (ETo) as a function of the main climatic data (air temperature, relative humidity, wind speed and sunshine duration) obtained in a conventional meteorological station at Governador Dix- Sept Rosado county. A model for determining the class A pan coefficient (Kt) was also proposed for that location. The regression and path analysis were used in evaluating the direct and indirect effects from each collected climatic elements on estimated ETo rates. ln both analyses the reference evapotranspiration was the dependent variable (Y) and the climate elements were the independent variables (X). According to the results, the Penman- Monteith method showed a better adequacy in estimating the ETo rates from the climatic elements data either for dally values or flve days averaged values. For the five days averaged values the evapotranspiration measuring equipment showed a substantial improvement in the coefñcient of determination. The regression and path analysis showed similar results emphasizing that the sunshine duration is the main clímatic element in the evapotranspiration process either as direct or indirect effect. lt was observed that the Kt values for the study area was only 0.73. thus much |ess then 0.85 determined by FAO.