Title: The performance of fuzzy regression method for estimating of reference evapotranspiration under controlled environment

Authors: Mohammad Javad Amiri; Abdol Rassoul Zarei; Jahangir Abedi-Koupai; Saeid Eslamian

Addresses: Department of Water Engineering, College of Agriculture, Fasa University, 74617-81189, Fasa, Iran ' Department of Natural Resources Science, College of Agriculture, Fasa University, 74617-81189, Fasa, Iran ' Department of Water Engineering, College of Agriculture, Isfahan University of Technology, 84156-83111, Isfahan, Iran ' Department of Water Engineering, College of Agriculture, Isfahan University of Technology, 84156-83111, Isfahan, Iran

Abstract: With the objective of evaluating the performance of fuzzy regression method for estimating the reference evapotranspiration in greenhouse, a lysimeter study was conducted to determine the evapotranspiration (ET_o) rates for grass crop. Daily outputs from model have been tested against reference evapotranspiration data computed by the lysimeter to assess the accuracy of the model. The estimated ET_o values from a fuzzy regression model using five input parameters, including maximum and minimum temperature, mean relative humidity, wind speed and solar radiation were obtained with RMSE = 0.68 mm/day, R² = 0.98. The accuracy of fuzzy 1 was the best but the accuracy of the fuzzy 3 was the worse for estimating daily evapotranspiration. The RMSE values of fuzzy 1, fuzzy 2, Fuzzy 3 were 0.68, 0.99 and 1.307, respectively. Thus, fuzzy 1 approaches work well for the data set used in greenhouse condition.

Keywords: evapotranspiration; fuzzy regression; lysimeter; meteorological variable.

DOI: 10.1504/IJHST.2019.096791

International Journal of Hydrology Science and Technology, 2019 Vol.9 No.1, pp.28 - 38

Received: 18 Feb 2016
Accepted: 17 Jun 2016
Published online: 11 Dec 2018 *

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