THE INFLUENCE OF ENSO AND IOD ON EXTREME RAINFALL IN INDONESIA IN THE FUTURE

• Main Author: Hanifa, Risyda
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/84995
• Institution: Institut Teknologi Bandung

Indonesia, as a maritime country straddling the equator and is located between the Indian and Pacific Oceans, is vulnerable to environmental disasters such as floods and landslides due to extreme rainfall. Overall, Indonesia’s average rainfall is influenced by interannual climate variations, such as the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD), with the greatest impact occurring during the SON season. This study aims to identify future changes in the influence of ENSO and IOD on extreme rainfall in Indonesia, specifically during the SON season. This study utilizes rainfall and sea surface temperature data form the CMIP6 climate model for the historical period (1985-2014) and future projections for the near-future (2031-2060) and far-future (2061-2090) under the SSP2-4.5 and SSP5- 8.5 climate scenarios. The methodology includes model evaluation using three statistical metrics, calculation of extreme rainfall using R95p index, calculation of the ENSO index using ONI, calculation of the IOD index using DMI, and analysis of the relationship between ENSO and IOD on extreme rainfall through linear regression. The results indicate that the changes in the influence of ENSO and IOD on extreme rainfall in Indonesia in the near-future period tends to be negative across most regions, except for Java, which shows positive changes. In the far-future period, the influence of ENSO in certain areas Kalimantan and IOD in southern Sumatra become positive. After removing the effects of ENSO and IOD separately, a complex relationship between the two becomes evident. For example, in the future period, the independent IOD has a value change in the southern region of Kalimantan from negative to positive. Significant changes due to ENSO and IOD on extreme rainfall are observed in North Kalimantan, reaching -80 mm/? due to ENSO and -180 mm/? due to IOD. These changes are projected to become more pronounced under the SSP5-8.5 climate change scenario.