The Indonesian Meteorology, Climatology, and Geophysics Agency (BMKG) has released its analysis of atmospheric dynamics for the second decade of October, predicting the potential emergence of the La Niña climate phenomenon in Indonesia.
La Niña is characterized by excessive rainfall in certain regions and is indicated by a drop in temperature below 0.5 degrees Celsius in the tropical Pacific Ocean.
BMKG Chief Dwikorita Karnawati stated during a recent meeting on hydrometeorological disaster anticipation that the La Niña phenomenon occurring in the Pacific is expected to increase monthly rainfall accumulation in Indonesia by 20-40% above normal levels.
According to BMKG’s monitoring of the Indian Ocean Dipole (IOD) and El Niño-Southern Oscillation (ENSO) indices, the IOD index has crossed the negative threshold (-1.11) but remains classified as neutral since it has only been one decade. The sea surface temperature anomaly in the Nino3.4 region also indicates conditions surpassing the La Niña threshold with an index of -0.64, but it has only persisted for one decade, maintaining a neutral ENSO status.
BMKG predicts that the neutral La Niña IOD will last until early 2025, while ENSO is likely to trend towards a weak La Niña starting in October 2024.
Deputy for Climatology at BMKG, Ardhasena Sopaheluwakan, confirmed that the development of the IOD and ENSO indices suggests La Niña is on the horizon. However, confirmation requires time, with a trend observation period exceeding one month.
Previously, BMKG’s Deputy for Meteorology, Guswanto, explained that La Niña during the early rainy season could lead to increased rainfall across most regions. The impact of La Niña on rainfall in Indonesia varies spatially and temporally, depending on the season, region, and the strength of the La Niña itself.
In addition to the influence of monsoon wind circulation and climate anomalies in the Pacific, the increase in rainfall in Indonesia is also affected by the propagation of atmospheric waves, including the Madden Julian Oscillation (MJO) and Kelvin waves from west to east, as well as Rossby waves from east to west.
BMKG’s analysis for the second decade of October 2024 shows rainfall varied from low (24%), medium (59%), to high-very high (17%). The nature of rainfall during this period was below normal (21%), normal (13%), and above normal (66%).
As of now, 27% of Indonesia is experiencing the rainy season, affecting regions including parts of Aceh, North Sumatra, Riau, West Sumatra, Jambi, parts of South Sumatra, Bengkulu, Bangka Belitung, parts of Banten, West Java, parts of Central Java, and several areas in Kalimantan, Sulawesi, Maluku, and Papua.
BMKG urges the public to remain vigilant and cautious of potential impacts from extreme weather conditions such as floods, landslides, flash floods, strong winds, and slippery roads. For the latest information, the public can access BMKG’s 24-hour weather information services through its website, social media, and applications.