Estudio comparativo entre modelos de estimación de radiación solar y déficit de presión de vapor en dos gradientes altitudinales

Abstract

The estimation of solar radiation (RS) and vapor pressure deficit (VPD) are a necessary process when there are no measurements of these variables in a region. This is the case in mountainous areas such as the Andes where there are insufficient measurements because of the cost and difficulty to obtain them. These variables are important in ecological and economic terms, and also to estimate reference evapotranspiration (ETO). This thesis presents a comparative study of 5 empirical models to estimate RS (Hargreaves-Samani, Allen, Annandale, Chen and Ertekin-Yaldiz) and 5 models to estimate VPD (FAO56 and 4 models Castellvi), all of them based on air temperature. Daily Rs and VPD data from 6 meteorological stations were used in two altitudinal gradients located in the Quinuas and ZhurucayEcohydrological Observatories (Azuay, Ecuador). The validation criteria were performed using different statistical indices. The results showed that the original RS models need calibration and validation before they provide valid estimations. The calibrated Rs models resulted in improved estimates in the two gradients. The Chen model showed the best results for all stations in the two gradients. The results of VPD models showed in Balzay (urban) a distinct performance. Favorable results were not obtained with any model only at weather station Campamento.This study has provided calibrated equations that can be used in the Andes of southern Ecuador for estimating RS and VPD.