Articles
HARGREAVES-SAMANI METHOD AND EVAPORATION PAN IN THE ESTIMATION OF REFERENCE EVAPOTRANSPIRATION
Article number
449_14
Pages
113 – 118
Language
Abstract
The availability of evaporation and temperature data during the irrigation season (June-September) for 13 years in a farm located in Eastern Sicily prompted a research aimed to compare the reference evapotranspiration (ETo) estimates obtained with the Hargreaves-Samani method (H-S) with those obtained through class A pan readings.
Results showed the utility of averaging estimates obtained through the two methods when reference evapotranspiration exceeded 5–6 mm day-1. Weekly coefficients of variations for H-S were rather low, not substantially differing from those for larger intervals: this gives strength to the opinion that H-S can be used also for intervals less than the ten days recommended.
Since deviations in single years’ monthly estimates from the 13-years averaged values were within narrow limits, it may be concluded that averaging "historical" values of H-S and class “A” pan for a period of (at least) a similar length -13 years- may yield a useful forecasting tool for water management in the particular environment.
Even in the absence of class “A” data, H-S alone may be useful in irrigation scheduling.
Due to its structure H-S may be employed to model changes in ETo depending on climate modifications.
Results showed the utility of averaging estimates obtained through the two methods when reference evapotranspiration exceeded 5–6 mm day-1. Weekly coefficients of variations for H-S were rather low, not substantially differing from those for larger intervals: this gives strength to the opinion that H-S can be used also for intervals less than the ten days recommended.
Since deviations in single years’ monthly estimates from the 13-years averaged values were within narrow limits, it may be concluded that averaging "historical" values of H-S and class “A” pan for a period of (at least) a similar length -13 years- may yield a useful forecasting tool for water management in the particular environment.
Even in the absence of class “A” data, H-S alone may be useful in irrigation scheduling.
Due to its structure H-S may be employed to model changes in ETo depending on climate modifications.
Authors
F. La Loggia, M. Pennisi, V. Sardo
Keywords
Class “A” pan, irrigation scheduling, historical data, data variability, climate changes
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