Evaluación del desempeño de indicadores meteorológicos e índices de vegetación para umbrales de sequía en Santa Elena

Abstract

This study aims to define agricultural drought thresholds for the parish of Colonche, in the province of Santa Elena. The need arises from the fact that precipitation deficits cause deterioration of vegetation cover, making it necessary to identify critical drought thresholds as an initial step toward risk reduction in agricultural territories and the generation of anticipatory actions in the face of drought events on the Ecuadorian coast. Time series of precipitation and temperature from CHIRPS (Climate Hazards Center InfraRed Precipitation with Station data) and ERA5-Land from the European Centre for Medium-Range Weather Forecasts were used to calculate meteorological indicators, along with vegetation indices (NDVI) derived from MODIS (Moderate-Resolution Imaging Spectroradiometer), a sensor aboard NASA’s Terra and Aqua satellites. Tools such as Google Earth Engine and Python were employed for data download, statistical processing, and generation of graphics. The results showed that SPI3 (the best-performing meteorological indicator) values lower than -1, together with low NDVI values, allowed the establishment of critical thresholds that reflected agricultural drought conditions in Colonche. In conclusion, the integration of meteorological indicators and vegetation indices successfully enabled the definition of agricultural drought thresholds, constituting a useful and replicable tool for risk management and the implementation of anticipatory actions in coastal territories of Ecuador. Keywords: drought thresholds, meteorological indicators, vegetation indices, risk management.