The El Niño-Southern Oscillation (ENSO) significantly impacts global weather, with strong El Niño events often linked to prolonged dry conditions in Southeast Asia. While some high-impact El Niño events have coincided with prolonged dry conditions, leading to droughts, the underlying causal mechanisms remain complex and inconsistent. In this study, we develop a minimal, datadriven model to quantify the conditions under which ENSO events amplify prolonged dry conditions risk in Southeast Asia. Unlike correlation-based approaches, our model identifies thresholds in sea surface temperatures and atmospheric patterns that increase the probability of prolonged dry conditions, highlighting both seasonal timing and intensity as critical factors. Our results show that when ENSO-induced anomalies exceed specific temperature and atmospheric thresholds, prolonged dry conditions probability rises significantly, aligning with observed historical droughts. Additionally, the model reveals periods where this link weakens due to competing regional climate factors, suggesting that certain conditions mitigate the typical ENSO-prolonged dry conditions connection. These findings provide a more nuanced understanding of ENSO-driven prolonged dry conditions variability, offering a probabilistic predictive framework with potential applications in climate adaptation, agricultural planning, and regional resource management.
I. INTRODUCTION
El Niño-Southern Oscillation (ENSO) is a naturally occurring climate phenomenon that affects weather patterns and precipitation across the globe [1]. ENSO is characterized by the cyclic warming and cooling of the tropical Pacific Ocean, which can lead to a wide range of impacts on global climate. El Niño (i.e. the positive phase of ENSO) which occurs when the sea surface temperature in the central and eastern Pacific is warmer than normal, is one of the most documented phases of ENSO [2].
