A Literature Review: Climate Variability in Indonesia and the Role of ENSO, IOD, and the Monsoon on Rainfall and Extreme Weather

ABSTRACT Climate variability in Indonesia is strongly influenced by ocean atmosphere dynamics in the Indo-Pacific region, particularly the El Niño Southern Oscillation (ENSO), the Indian Ocean Dipole (IOD), and the Asian Australian monsoon system. These phenomena play a major role in shaping rainfall distribution, extreme weather events, and oceanic conditions such as the Indonesian Throughflow (ITF). Transitions in ENSO and IOD phases frequently trigger severe dry or wet anomalies, making their understanding essential for climate early warning systems and hydrometeorological disaster mitigation in Indonesia.This literature review aims to analyze and synthesize findings from the past two decades regarding the influence of ENSO, IOD, and monsoon dynamics on rainfall variability and extreme weather conditions in Indonesia. A systematic literature review was conducted using ten verified scientific articles published between 2014 - 2025. Articles were obtained from reputable databases such as Wiley, MDPI, Springer, IOP, and ScienceDirect. Selection criteria included relevance to Indonesia, links to ENSO/IOD/monsoon dynamics, and utilization of observational or climate modeling data. The review indicates that El Niño consistently reduces rainfall across Indonesia, especially during the dry season, while La Niña enhances rainfall over many regions. The IOD acts as a key modulator, with positive IOD events intensifying El Niño induced droughts and negative IOD events amplifying La Niña related wet conditions. Several studies also highlight asymmetric atmospheric and oceanic responses, including weakening or strengthening of the ITF under certain ENSO IOD combinations. The interaction among these phenomena shows its strongest impact during the dry season when the southeast monsoon is dominant. ENSO, IOD, and monsoon dynamics collectively shape Indonesia’s climate variability. The combined ENSO–IOD phase strongly determines the magnitude of rainfall anomalies, both dry and wet. Comprehensive understanding of their interactions is crucial for improving seasonal forecasting, disaster mitigation, and water resource management in Indonesia. Keyword: ENSO, IOD, Monsoon, Climate Variability, Rainfall