Evaluation of the NASA-POWER product for estimating reference evapotranspiration in southeastern Córdoba

Abstract

The quantification of reference evapotranspiration (ETo) is useful for different applications. However, its estimation is limited by the lack of terrestrial observation instruments and networks. Currently, satellite gridded reanalysis products are available as an alternative to estimate spatially explicit meteorological variables at local and regional scales. The objective of this work was to evaluate the estimation of daily ETo using the NASA-POWER reanalysis product in southeastern Córdoba. Through the Penman-Monteith model, daily ETo was estimated from temperature, humidity, wind speed and solar radiation data obtained from two conventional weather stations and the NASA-POWER product. The results showed that NASA-POWER accurately estimated ETo when compared to that observed at the stations, with an R2 close to 0.90 and errors of less than 1 mm.day-1. During the summer NASA-POWER overestimated ETo, with larger errors in the estimation; while in winter the overestimation occurred in values higher than 2 mm.day-1. In the spring and autumn months, the adjustment was greater, although the errors were slightly higher than in the winter months. It is concluded that the NASA-POWER product can reconstruct the lack of meteorological records in southeastern Córdoba and, from this, estimate ETo with low error.