CR 44:27-40 (2010)  -  DOI: https://doi.org/10.3354/cr00919

ABSTRACT: We studied the sensitivity of reference evapotranspiration (ET_o) to global warming in Spain at the end of the 21st century. The FAO-56 Penman-Monteith equation was used to estimate ET_o, and we examined the sensitivity of the latter to changes in temperature and relative humidity. Changes in stomatal resistance in response to increased CO₂ concentration were not evaluated, nor were the changes in wind velocity and solar radiation. Different scenarios were used for estimation of future ET_o in different river basins as a consequence of trends in the maximum and minimum temperatures and maximum and minimum humidities during the period 1973–2002, as observed from 38 meteorological stations. The temperature increases ranged between 0.3 and 0.7°C decade^–1, and the relative humidities fluctuated between 0.1 and –3.7% decade^–1. Four scenarios were simulated that considered the variations in linear tendency of the maximum and minimum temperatures and maximum and minimum relative humidities. The trends of the 4 scenarios were incorporated with the data from 338 agrometeorological stations to estimate future ET_o. In all cases, there was an annual increase in ET_o of 11, 21, 36 and 7% above the annual ET_o (1196 mm) for Scenarios 0, 1, 2 and 3, respectively. The river basin most affected by these changes was the Ebro River valley. The most affected months were May, June, July and August, while the least affected months were November, December and January.

KEY WORDS: Evapotranspiration · Climate change · Temperature · Relative humidity · Spain

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Cite this article as: Moratiel R, Durán JM, Snyder RL (2010) Responses of reference evapotranspiration to changes in atmospheric humidity and air temperature in Spain. Clim Res 44:27-40. https://doi.org/10.3354/cr00919 Export citation Share:    Facebook - - linkedIn