Resumo

UNIGARRO, Carlos Andrés et al. Evaluation of four degree-day estimation methods in eight Colombian coffee-growing areas. Agron. colomb. [online]. 2017, vol.35, n.3, pp.374-381. ISSN 0120-9965.  https://doi.org/10.15446/agron.colomb.v35n3.65221.

Methods to estimate the accumulation of degree-days based on maximum and minimum temperaturesare are commonly used to determine relationships or to adjust phenological models based on the "physiological time". Degree-days are obtained indirectly by these methods, this information is not generally available on hourly or shorter time scales due to the type of equipment used to record data or a data loss in historical time series. To compare the performance of such methods, degree-days were estimated with four indirect methods in eight Colombian locations during 1 year. Each indirect method was evaluated in comparison to the numerical integration method by the trapezoidal rule (reference method) using temperatures recorded every 5 min. Based on the percent bias error, the methods proposed by Arnold, Ometto and Snyder tend to overestimate thermal time, whereas the Villa-Nova method underestimates this time, but with a lower performance as regards to the previous ones.

Palavras-chave : thermal time; temperature; numerical integration; linear regression; bias.

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