Quantifying the impact of climate variables on reference evapotranspiration in Pearl River Basin, China

ABSTRACT

The impact of climate variables on monthly reference evapotranspiration (ET_o) is a critical issue in water resources management and irrigation planning. The spatio-temporal contribution of climate variables to ET_o in the Pearl River Basin (PRB), China, from 1960 to 2016 were calculated based on sensitivity and relative change of each climatic variable. The results show that annual ET_o total decreased by 1.64% and diminished in magnitude from the southeast to the northwest. Sunshine duration, wind speed and relative humidity decreased by 15.5%, 7.4%, and 4.0%, respectively, while average temperature increased by 4.25%. The ET_o showed a positive sensitivity to all variables except relative humidity, which showed a negative sensitivity. Sunshine duration had the highest contribution of −4.26%, and the overall decrease in ET_o was mainly caused by the declines in sunshine duration and wind speed, which offset the positive impact of rises in average temperature and reduction in relative humidity.

KEYWORDS:

• evapotranspiration
• spatio-temporal
• climate variable
• sunshine duration
• Pearl River Basin

Editor A. Castellarin Guest editor M. Borga

Editor A. Castellarin Guest editor M. Borga

Acknowledgements

We appreciate the assistance of the editors, Dr Tegos and another anonymous reviewer for their critical comments and constructive suggestions on the paper.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

Portions of Paw U’s work in this study were supported by the US National Institute of Food and Agriculture [CA-D-LAW-4526H and CA-D-LAW-7214-RR].