Loading...
Publication
Avaliação da evapotranspiração de refer~encia (ETO) por uma mini-tina evaporimétrica
| Name: | Description: | Size: | Format: | |
|---|---|---|---|---|
| 5.73 MB | Adobe PDF |
Abstract(s)
Este estudo teve como objetivo verificar a viabilidade de utilização de uma minitina como método expedito na estimativa da taxa de evapotranspiração de referência, em agricultura e espaços verdes, comparando-a com a tina evaporométrica classe A e com o método de Hargreaves.
O estudo decorreu entre o final de fevereiro e o início de agosto de 2016 e foi efetuado junto à estação meteorológica do Instituto Português do Mar e da Atmosfera (IPMA), situada no INIAV - Pólo de Elvas.
O dispositivo experimental foi constituído por uma tina evaporimétrica classe A e 9 mini-tinas com 3 níveis de profundidade (P1 - 0,85 cm, P2.- 3,5 cm e P3 - 6,5 cm) construídas para o efeito.
Os dados de evaporação foram comparados com a ETo obtida pelo método de Penman-Monteith (PM), utilizado como método padrão. Os resultados mostram que tanto a tina classe A como as mini-tinas e o método de Hargreaves, necessitam de uma calibração distinta para o inverno e para o verão. Comparativamente a PM a mini-tina 2 (profundidade 3,5 cm) foi a que apresentou o coeficiente de determinação mais elevado,
similar ao obtido por Hargreaves.
Em futuros trabalhos, com as mini-tinas, sugere-se fixar a profundidade 2 e testar outros parâmetros, como por exemplo, diferentes aberturas da janela de evaporação, incluir o fator cor e ainda considerar a introdução do fator sombra. Tal facto seria útil para a utilização, em particular nos espaços verdes, pois permitiria mais
facilmente ocultar o impacto visual da colocação do sensor.
This study aimed to verify the feasibility of the use of a mini-pan evaporation as an expedited method in estimate the evapotranspiration rate in agriculture and greenscapes, comparing it to the class A pan and with the Hargreaves method. The study took place between the end of February and the beginning of August 2016 and was carried out near the weather station of the Instituto Português do Mar e da Atmosfera (IPMA), located in INIAV - Elvas. The experimental device consisted of a class A pan and 9 mini-pans with 3 levels deep (P1 - 0.85 cm, P2 - 3.5 cm and P3 - 6.5 cm) that were made for this experience. The evaporation data were compared with ETo obtained by the Penman-Monteith (PM) method that was used as a standard method. The results show that both class A pan and the mini-pans and also the Hargreaves method, require a separate calibration for the winter and the summer. Comparatively to PM, mini-pan 2 (depth 3.5 cm) was the one that presented the highest coefficient of determination, similar to that obtained by Hargreaves. In future works, with the mini-pans, it is suggested to fix depth 2 and test other parameters, for example different openings of the evaporation window, include the color factor and still consider the introduction of the shadow factor. That would be useful particularly in greenscapes, since it would be easier to hide the sensor placement.
This study aimed to verify the feasibility of the use of a mini-pan evaporation as an expedited method in estimate the evapotranspiration rate in agriculture and greenscapes, comparing it to the class A pan and with the Hargreaves method. The study took place between the end of February and the beginning of August 2016 and was carried out near the weather station of the Instituto Português do Mar e da Atmosfera (IPMA), located in INIAV - Elvas. The experimental device consisted of a class A pan and 9 mini-pans with 3 levels deep (P1 - 0.85 cm, P2 - 3.5 cm and P3 - 6.5 cm) that were made for this experience. The evaporation data were compared with ETo obtained by the Penman-Monteith (PM) method that was used as a standard method. The results show that both class A pan and the mini-pans and also the Hargreaves method, require a separate calibration for the winter and the summer. Comparatively to PM, mini-pan 2 (depth 3.5 cm) was the one that presented the highest coefficient of determination, similar to that obtained by Hargreaves. In future works, with the mini-pans, it is suggested to fix depth 2 and test other parameters, for example different openings of the evaporation window, include the color factor and still consider the introduction of the shadow factor. That would be useful particularly in greenscapes, since it would be easier to hide the sensor placement.
Description
Keywords
Evapotranspiração mini-tina tina classe A Penman-Monteith Hargreaves evapotranspiration mini-pan class A pan