Analysis of Mesoscale Convective Complex during Madden Julian Oscillation Phase 4 (Case Study: Heavy rain in Cilacap on Sept 16-17, 2016)

Abstract

This research aims to analyze the heavy rain which accompanied by severe winds, caused floods and landslides in several of sub-districts in Cilacap, Central Java on 16-17 September 2016 that coincides with the phase 4 of Madden Jullian Oscillation (MJO) event. In the same time, also found a Mesoscale Convective Complex (MCC) in the around Central Java. MCCs were identified by infrared satellite imagery from Himawari 8 using an algorithm that combines criteria of cloud coverage, eccentricity, and cloud lifetime. The data used is a combination of observation data, satellite data and reanalysis data. This study results that there is an increase in vertical velocity accompanied by strong negative vorticity since the development of MCC until it reached its mature phase, then the vertical velocity decreases as the cloud systems disseminated. These results indicate there is the evolution of MCC convective cells from growth until dissipation. Throughout its lifetime the MCC system moves south-east into the Indian Ocean and is decapitated there. Based on GSMaP rainfall data it was observed that in Central Java area especially Cilacap area has extreme rainfall which caused by MCC activity. The influence of MCC on significant rainfall is also supported by the existence of MJO phase 4. The significant increase in rainfall when phase 4 active MJO is followed by the MCC. The value of rainfall intensity when MJO followed by the presence of MCC is greater than in the absence of MCC.