Sensitivity of the Penman-Monteith reference evapotranspiration equation to meteorological variables for Puerto Rico

Hydrology
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Abstract

Spatiotemporal variations in reference evapotranspiration (ETo) are sensitive to the meteorological data used in its estimation. The sensitivity of the ASCE standardized ETo equation to meteorological variables from GOES-PRWEB dataset was evaluated for the island of Puerto Rico. Island wide, ETo is most sensitive to daily mean relative humidity (RHmean), followed by solar radiation, daily maximum (Tmax) and minimum (Tmin) air temperatures, and wind speed with average absolute relative sensitivity coefficients (SCs) of 0.98, 0.57, 0.50, 0.27, and 0.12, respectively. The derived SCs guided the prioritization of bias correction of meteorological data for ETo estimation from two downscaled climate models (CNRM and CESM). The SCs were applied to evaluate how meteorological variables contribute to model errors and projected future changes in ETo from 1985–2005 to 2040–2060 at irrigated farms in the south. Both models project a 5.6% average increase in annual ETo due to projected increases in Tmax and Tmin and a decrease in RHmean. Despite ETo being most sensitive to relative changes in RHmean, the contributions from RHmeanTmax, and Tmin to future changes in ETo are similar. CESM projects increases in ETo in March, November, and December, increasing the potential for crop water stress. Study limitations are discussed.

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Publication type Article
Publication Subtype Journal Article
Title Sensitivity of the Penman-Monteith reference evapotranspiration equation to meteorological variables for Puerto Rico
Series title Hydrology
DOI 10.3390/hydrology10050101
Volume 10
Issue 5
Year Published 2023
Language English
Publisher MDPI
Contributing office(s) Caribbean-Florida Water Science Center
Description 101, 28 p.
Country United States
Other Geospatial Puerto Rico
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