The Effect of ENSO on Seasonal Rainfall Using the Monte-Carlo Bootstrap Method in the Southern Part of Java, Indonesia

ENSO is a global climate phenomenon that has been able to affect weather and climate conditions in Indonesia, especially in the southern part of Java Island, which is represented by Yogyakarta province. Subseasonal to seasonal (S2S) is a seasonal period that tries to bridge the gap between a relatively short period and a climate that has a relatively long period. The author has conducted a study that aims to determine the effect of the global ENSO phenomenon on the increase and decrease in rainfall in the southern part of the Java island region during the S2S season. In this study, the data obtained from the Nino 3.4 data and seasonal rainfall data in The southern part of Java, which is represented by Yogyakarta province in the years 2001–2022 were used. The method used is the Monte-Carlo Bootstrap permutation resampling method. The results show that in general the southern part of the Java Island region is affected by El Nino and La Nina phenomena both in the peak period of the rainy season and the peak of the dry season of JFM, JJA, ASO, and OND although the responses from several sample areas have different effects.