Rainfall intermittency in the Colombian Andes and its modulation by ENSO

Rainfall intermittency is a key feature of precipitation variability in mountainous regions, influencing hydrological dynamics across multiple temporal scales. This study analyzes the spatial and temporal characteristics of rainfall intermittency in the Colombian Andes using burstiness (B) and memory (M) metrics derived from daily precipitation data. We combine quality-controlled rain gauge observations from IDEAM with gridded CHIRPS rainfall estimates to examine intermittency patterns across aggregation scales from 1 to 15 days and to evaluate their modulation by the El Niño–Southern Oscillation (ENSO). The results show coherent regional structures in both B and M, with systematic changes as a function of temporal aggregation, and reveal statistically detectable ENSO-related differences that become more evident at multi-day scales. As a complementary analysis, rainfall intermittency metrics are compared between drainage basins with documented debris-flow occurrence and basins without recorded events, using non-parametric statistical tests. While differences in burstiness are generally small, memory exhibits statistically significant contrasts at longer aggregation scales. Overall, the study provides a consolidated characterization of rainfall intermittency in the Colombian Andes and documents its modulation by ENSO, offering a climatic context for exploring potential links between rainfall temporal organization and hydro-geomorphic processes.