Title: Empirical equation for estimating sunshine hours, and comparison of reference evapotranspiration models in temperate Kashmir Valley, India

Authors: Syed Mohsin; M.A. Lone

Addresses: Department of Civil Engineering, National Institute of Technology, Srinagar, Jammu and Kashmir, India ' Department of Civil Engineering, National Institute of Technology, Srinagar, Jammu and Kashmir, India

Abstract: The availability of sunshine hours (SSH) data is central to many agrometeorological, hydrological, and solar applications. However, records of SSH may not be available for all stations. In such situations, an alternate method for the estimation of SSH becomes indispensable. In this study, the linear regression technique was used to develop a model for estimating mean monthly SSH using monthly averages of routinely recorded meteorological parameters for Kashmir Valley, India. Coefficient of determination (R²) and residual analysis were used to evaluate the developed model. For the stations where SSH data were available, a comparison of the actual and predicted reference evapotranspiration (ETO) calculated using eight models was made. The comparison showed a firm agreement between the actual and predicted ETO. Based on statistical indicators of the standard error of estimate and Willmot's index, the ETO models were ranked in order of their performance in comparison to the FAO-56 Penman-Monteith equation.

Keywords: Penman-Monteith equation; multiple linear regression; ranking; sunshine hours; SSH; reference evapotranspiration; ET_O; India.

DOI: 10.1504/IJHST.2023.128716

International Journal of Hydrology Science and Technology, 2023 Vol.15 No.2, pp.97 - 111

Received: 29 Jan 2021
Accepted: 03 Jun 2021
Published online: 02 Feb 2023 *

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