Characteristics of the Extreme Rainfall over Indonesian Equatorial Region based on the Madden-Julian Oscillation Index Data Analysis

Abstract

Indonesia Maritime Continent (IMC) is one the most important region at the equator which affected by many atmospheric phenomena, especially Madden-Julian Oscillation and Monsoon. Asian Winter Monsoon causes the increasing of rainfall in several places in Indonesia in December-January-February (DJF), and since MJO related to a propagation of convective cloud, somehow it affects the rainfall variability in equator, especially over Indonesia. Interaction of both phenomena simultaneously bring rainfall is increasing in Indonesia, especially in Western Part of Indonesia. Therefore, a research about the impact of MJO in rainfall especially in Bandung and other cities over Indonesia is important. This study aims to investigate impacts of MJO events on the rainfall variability in Bandung and other cities focusing when Asian Winter Monsoon (December-January-February/DJF) for period of DJF 2002/03 – DJF 2012/13 passing over Indonesia. The results show that from 10 MJO events in period DJF 2002/03 – DJF 2012/13, the event increased the rainfall continuously in phase 3, phase 4, and phase 5. In phase 3, the increasing happened in every station except Supadio in Pontianak with the total precipitation > 30 mm/day. The condition of rainfall in phase 4 fluctuates in every station, but with the dominant increasing in Equator. In phase 5, the decreasing of rainfall happened in North of the Equator and Equator, while in South of Equator, the rainfall in Cengkareng Station in Jakarta increased about 20% but decreased about -42% in Bandung Station.