Performance of Twelve Mass Transfer Based Reference Evapotranspiration Models under Humid Climate

Authors

Koffi Djaman, New Mexico State UniversityFollow
Komlan Koudahe, ADA Consulting AfricaFollow
Mamadou Sall, Institut Senegalais de Recherches Agricoles, Centre de Saint Louis, Saint Louis, Sénégal
Isa Kabenge, Makerere University
Daran Rudnick, University of Nebraska - LincolnFollow
Suat Irkmak, University of Nebraska-LincolnFollow

Document Type

Article

Date of this Version

2017

Citation

Djaman, K., Koudahe, K., Sall, M., Kabenge, I., Rudnick, D. and Irmak, S. (2017) Performance of Twelve Mass Transfer Based Reference Evapotranspiration Models under Humid Climate. Journal of Water Resource and Protection, 9, 1347-1363. https://doi.org/10.4236/jwarp.2017.912086

Comments

Copyright © 2017 by authors and Scientific Research Publishing Inc. This work is licensed under the Creative Commons Attribution International License (CC BY 4.0).

Abstract

Reference evapotranspiration is very important parameter in the hydrological, agricultural and environmental studies and is accurately estimated by the FAO Penman-Monteith equation (FAO-PM) under different climatic conditions. However, due to data requirement of the FAO-PM equation, there is a need to investigate the applicability of alternative ETo equations under limited data. The objectives of this study were to evaluate twelve mass transfer based reference evapotranspiration equations and determine the impact of ETo equation on long term water management sustainability in Tanzania and Kenya. The results showed that the Albrecht, Brockamp-Wenner, Dalto, Meyer, Rohwer and Oudin ETo equations systematically overestimated the daily ETo at all weather stations with relative errors that varied from 34% to 94% relative to the FAO-PM ETo estimates. The Penman, Mahringer, Trabert, and the Romanenko equations performed best across Tanzania and the South Western Kenya with root mean squared errors ranging from 0.98 to 1.48 mm/day, which are relatively high and mean bias error (MBE) varying from −0.33 to 0.02 mm/day and the absolute mean error (AME) from 0.79 to 1.16 mm/day. For sustainable water management, the Trabert equation could be adopted at Songea, the Mahringer equation at Tabora, the Dalton and/or the Rohwer equations at Eldoret, the Romanenko equation at Dodoma, Songea and Eldoret. However, regional calibration of the most performing equation could improve water management at regional level.