Hydrological responses to ENSO variability across Peruvian catchments

The El Niño Southern Oscillation (ENSO) is a major driver of hydroclimatic variability, yet its influence on streamflow across Peru remains insufficiently quantified at the national scale. This study analyses ENSO-driven streamflow responses in 44 Peruvian catchments during 1981–2024 using observations and hydrological simulations within a multiscale framework. The analysis integrates seasonal regimes, anomaly patterns, and ENSO–streamflow teleconnections using multiple climate indices. Results reveal a clear regional structure, with contrasting responses between the northern Pacific coast and the Andean–Amazonian regions. The northern Pacific shows positive associations with eastern Pacific indices, while other regions exhibit negative relationships with central Pacific indices. These patterns are consistent across temporal scales, with rapid coastal responses and weaker inland signals. The findings highlight regionally differentiated ENSO controls on streamflow variability in Peru, with implications for monitoring and forecasting, and relevance for South America.