Evapotranspiração de referência de Penman-Monteith, padrão FAO (1998), a partir de dados de temperaturas máxima e mínima de Minas Gerais

• Autor(a) principal: Lima, Evaldo de Paula
• Data de Publicação: 2005
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/5287
• topic: Evapotranspiração de referência; Modelo de Penman-Monteith; Temperatura máxima e mínima; reference evapotranspiration; Model of Penman-Monteith; Maximum and minimum temperature; CNPQ::CIENCIAS EXATAS E DA TERRA::GEOCIENCIAS

Meteorological data of 27 stations, compiled from the Instituto Nacional de Meteorologia (INMET), were used to estimate reference evapotranspiration (ETo) for the State of Minas Gerais. ETo values were estimated by the conventional FAO Penman-Monteith method using standard climatic data and by an alternative approach that requires only the maximum and minimum temperatures. In order to use the alternative method, partial water vapor pressure and solar radiation were estimated from meteorological data. Fixed wind speed values of 1, 2, 3 and 5 ms-1 were used for each combination of maximum and minimum temperatures (Tmax and Tmin) in locations where wind speed data was not available. To select the best methodology for estimating solar radiation, a comparison was carried out between solar radiation calculated with the Angström method and solar radiation determined with the maximum and minimum temperatures. A software program, denoted by Reference Evapotranspiration Calculator (REF-ET), was also developed to calculate the reference evapotranspiration using data of daily average relative humidity, daily wind speed, and maximum and minimum temperatures. ETo calculated with the REF-ET program was used to evaluate ETo based in Tmax and Tmin. A linear regression analysis was carried out to analyze the final estimated values of ETo against output from REF-ET program, for all four values of wind speed and four time intervals (weekly, ten days, biweekly and monthly). The Geographical Information System (SIG) was used to generate evapotranspiration maps for the State of Minas Gerais from geospatialized values of ETo. Results of the reference evapotranspiration determined with the alternative method were satisfactory in a large part of the state, mainly in the half East of the State and for wind speeds from 1 to 2 m/s.