MJO Modulation on Diurnal Rainfall over West Java during Pree-Moonson and Strong el Nino Periods

This study was conducted to determine the MJO modulation ondiurnal rainfall in West Java during the pre-monsoon and strong El NiBo periods in 2015 over West Java. The data used is a combination of satellite data, reanalysis data, radar stations data, and numerical weather prediction of Weather Research and Forecasting (WRF) data with spatial resolution of 5 km. The results confirmed that the strong MJO in 4 and 5 phases has modulated the amplitude of diurnal rainfall increase significantly over West Java in phase of lag+1. Modulation on diurnal cycle of rainfall was also indicated by the persistence of the rainfall and the formation of two peaks of maximum rainfall in the afternoon and early morning. In addition, modulation of rainfall for the southern part of Java was 50% greater than the north. Moreover, the MJO modulation mechanism was characterized by the formation of an active and extending of Meso-scale Convective System (MCS) which has a cycle of up to 12 hours and persistent from November 7-9 over West Java.