Title: Temporal analysis of reference evapotranspiration to detect variation factors

Authors: Mohammad Valipour; Mohammad Ali Gholami Sefidkouhi

Addresses: Department of Water Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran ' Department of Water Engineering, Sari Agricultural Sciences and Natural Resources University, Sari, Iran

Abstract: There are many factors that can change reference evapotranspiration (ET0). In this study, after comparison of six reference evapotranspiration equations, variations of each model have been investigated to detect main factor(s) of temporal changes of ET0 from 1981 to 2010 in Goragn, Iran. Although Priestley-Taylor (PT) estimates ET0 is more identical to FPM than the other equations during 30-year period, the results show that accuracy of PT is reduced after 2000. The study of variations of temperature, relative humidity, wind speed, and sunshine, underlines that there is a considerable difference between the averages of the weather variables before and after 2000. Compared to 1981-1999, the average of wind speed has been increased more than three times after 2000 that it introduces the wind speed as the most important variable for changes of ET0 and alarms a climatic change in Gorgan, Iran.

Keywords: climatic change; Iran; Mann-Kendall test; trend analysis; wind speed.

DOI: 10.1504/IJGW.2018.090403

International Journal of Global Warming, 2018 Vol.14 No.3, pp.385 - 401

Received: 16 Jun 2016
Accepted: 14 Oct 2016
Published online: 14 Mar 2018 *

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