Recent trends and enso influence on droughts in northern chile: an application of the standardized precipitation evapotranspiration index

Abstract

Northern and central Chile is one of the driest regions of the Arid-Americas with increasing demands on finite water supplies. The region faces recurrent droughts that cause important economic damages. The need to better monitor drought and study changes in their main properties is important for disaster risk management. The aim of this work is to apply the Standardized Precipitation Evapotranspiration Index (SPEI) to detect trends of dry periods of different magnitude as well as to describe their association with El Niño phenomenon in the Coquimbo region. Data shows that dry events are frequent in the region, and that spring and summer show negative trends (i.e. increasing dryness) in most of the stations analyzed. Significant trends for SPEI values are in the order of &minus0.05 yr&minus1. The occurrence of dry conditions of different magnitude has increased over the last decades, and the duration of extreme climatic events has slightly increased as well. These results are consistent with future climatic projections and represent a major challenge for water resources management and the operation of existing reservoirs.