Journal Article

FZJ-2016-03239

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Estimation of Turc reference evapotranspiration with limited data against the Penman-Monteith Formula in Senegal

Diouf, O. C. (Corresponding author) ; Weihermüller, L.FZJ* ; Ba, K. ; Faye, S. C. ; Faye, S. ; Vereecken, H.FZJ*

2016
Istituto Agronomico per l'Oltremare Florence

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Please use a persistent id in citations: doi:10.12895/jaeid.20161.417

Abstract: Estimation of daily evapotranspiration (ET0) is required for efficientirrigation management in Senegal but physically based equations such as thePenman–Monteith (PM) approach need large inputs data which are not alwaysavailable. Therefore empirical approaches such as Turc’s formula are often used.Unfortunately, This latter showed high annual ET0 compared to FAO Penman–Monteith (FAO-PM) ET0 for stations in this region. Moreover, Turcunderestimates mean daily ET0 for the dry season and overestimates ET0 forthe wet season. For reevaluation, Turc’s empirical parameters (a and b) werefitted to match FAO-PM ET0, whereby the fitting did not improve the predictionsubstantially and only assuming C being independent on relative humidityyielded better agreement. In a second step universal a and b parameters wereestimated for different stations in Senegal. The results indicate that one set ofparameters (a and b) can be used to predict all station ET0 with fairly highaccuracy indicated by a R2 of 0.80 and an RMSE of 0.71 mm day-1. Based onthese findings we propose to use Turc’s approach in Senegal only with theparameters a = 0.16 and b = 29.19 with the constrain that C is independent onrelative humidity.

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Contributing Institute(s):

1. Agrosphäre (IBG-3)

Research Program(s):

1. 255 - Terrestrial Systems: From Observation to Prediction (POF3-255) (POF3-255)

Appears in the scientific report 2016

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