Comparison of sum-of-hourly and daily time step standardized ASCE Penman-Monteith reference evapotranspiration
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Date
2018
Journal Title
Journal ISSN
Volume Title
Publisher
Theoretical and Applied Climatology
Abstract
The objective of this study was to quantify differences
associated with using 24-h time step reference evapotranspiration
(ETo), as compared with the sum of hourly ETo
computations with the standardized ASCE Penman-Monteith
(ASCE-PM) model for semi-arid dry conditions at Fanaye and
Ndiaye (Senegal) and semiarid humid conditions at Sapu (The
Gambia) and Kankan (Guinea). The results showed that there
was good agreement between the sumof hourly ETo and daily
time step ETo at all four locations. The daily time step
overestimated the daily ETo relative to the sum of hourly
ETo by 1.3 to 8% for the whole study periods. However, there
is location and monthly dependence of the magnitude of ETo
values and the ratio of the ETo values estimated by both
methods. Sum of hourly ETo tends to give higher ETo during
winter time at Fanaye and Sapu, while the daily ETo was
higher from March to November at the same weather stations.
At Ndiaye and Kankan, daily time step estimates of ETo were
high during the year. The simple linear regression slopes between
the sum of 24-h ETo and the daily time step ETo at all
weather stations varied from 1.02 to 1.08 with high coefficient
of determination (R2 ≥ 0.87). Application of the hourly ETo
estimation method might help on accurate ETo estimation to
meet irrigation requirement under precision agriculture
Description
Keywords
Sum-of-hourly, ASCE Penman-Monteith, Evapotranspiration
Citation
Djaman, K., Irmak, S., Sall, M., Sow, A., & Kabenge, I. (2018). Comparison of sum-of-hourly and daily time step standardized ASCE Penman-Monteith reference evapotranspiration. Theoretical and Applied Climatology, https://doi.org/10.1007/s00704-017-2291-6