Joint Distribution Analysis of Forest Fires and Precipitation in Response to ENSO, IOD, and MJO (Study Case: Sumatra, Indonesia)

Abstract

To evaluate the impact of the El Niño Southern Oscillation (ENSO), Indian Ocean Dipole (IOD), and Madden Julian Oscillation (MJO) on the occurrence of land and forest fire in Sumatra, copula-based joint distribution analysis and quadrant analysis (for extreme events) were carried out in this research. This research used dry spells (number of days without rain) and precipitation anomalies as climate indicators and hotspots as land and forest fire indicators. Using data spanning from 2001 to 2020, this research shows that ENSO and IOD strongly influence hotspots in Sumatra with monsoonal-type precipitation. Even though the impact is not linear, the probability of a higher number of hotspots occurring increases significantly, especially during strong El Niño and weak El Niño combined with positive IOD. Furthermore, the results show that moderate El Niño has a similar impact to weak El Niño on the affected area, while weak El Niño combined with positive IOD can result in effects similar to robust El Niño impact. Meanwhile, this research has shown that the MJO affects hotspots in the first dry season of Sumatran areas that have equatorial-type precipitation. Although its impact on dry spell–precipitation anomaly dependency is unclear, phases 6,7, and 8 of MJO significantly increase dry spell–hotspot dependency during dry conditions.