Análisis del Comportamiento Extremo de la Temperatura y la Precipitación y su Relación con los Fenómenos de Variabilidad Climática (ENOS) y la Vulnerabilidad Hídrica en la Cuenca del Río Guáitara, Departamento de Nariño

Abstract

In this study, the trend of precipitation and extreme temperatures was analyzed in relation to the El Niño and La Niña climatic phenomena in the Guáitara River basin during the period 1991-2020. Daily rainfall data, maximum and minimum temperatures were used, with which climate indices were generated with two tools for analysis: RClimTool and RClimDex. The results revealed an increase in annual precipitation across much of the basin, along with a decrease in consecutive dry days (CDD) and an increase in consecutive wet days (CWD). Furthermore, maximum and minimum temperatures showed significant increases during these periods, evidencing a positive trend in the basin related to the TXX, TXN, TNN and TNX indices; Likewise, an inverse relationship was found between precipitation trends and the El Niño phenomenon, with a decrease in rainfall between 1992 and 2015, and an increase during La Niña in 1999 and 2011. Temperatures increased during El Niño, highlighting in 2015- 2016 and 2019, while they were lowest during La Niña in 1998-2001 and 2008. Regarding water vulnerability, it was found that under normal conditions more than 65% of the basin area suffers from high water shortages, and this figure increases to more than 88% in dry years. This behavior is related to the aforementioned trends of the CWD and CDD indicators in areas with high water shortages. These findings provide crucial information for the formulation of adaptation and risk management strategies in the face of climate variability in the Guáitara River basin. They also highlight the importance of monitoring and planning measures to guarantee the availability of water resources in the region, especially in extreme climate events such as El Niño and La Niña.