Prediction Model Development Madden Julian Oscillation (MJO) based on the results of data analysis Real Time Multivariate MJO (RMM1 and RMM2).
Abstract
Background of this research is the importance of study on the Madden Julian Oscillation, the dominant oscillation in the equator area. MJO cycle showed by cloud cluster growing in the Indian Ocean then moved to the east and form a cycle with a range of 40-50 days and the coverage area from 10N-10S. Method that used to predict RMM is Box-Jenkins based on ARIMA (Autoregressive Integrated Moving Average) statistical analysis. The data used RMM daily data period 1 March 1979 –1 March 2009 (30 years). RMM1 and RMM2 is an index for monitoring MJO. This is based on two empirical orthogonal functions (EOFs) from the combined average zonal 850hPa wind, 200hPa zonal wind, and satellite-observed Outgoing Longwave Radiation (OLR) data. The results in form of the Power Spectral Density (PSD) graph Real Time Multivariate MJO (RMM) and long wave radiation (OLR = Outgoing Longwave Radiation) at the position 100°BT, 120°BT, and 140°BT that show the wave pattern (spectrum pattern) and clearly shows the oscillation periods. There is a close relation between RMM1 with OLR at the position 100oBT that characterized the PSD value about 45 day. Through Box-Jenkins method, the prediction model that close to time series data of RMM1 and RMM2 is ARIMA (2,1,2), that mean the forecasts of RMM data for the future depending on one time previously and the error one time before. Prediction model for RMM1 is Zt = 1.681 Z t-1 – 0.722 Z t-2 + 0.041 Zt-3 - 0.02 at-1 - 0.05 at-2.. Prediction model for RMM2 is Zt = 1.714 Zt-1 – 0.764 Zt-2 - 2 + 0.05 Zt-3 - 0.109 at-1 - 0.05 at- 2.. The flood case in Jakarta January-February 1996 and 2002 are one of real evidence that made the MJO prediction important. MJO with active phase dominant cover almost the entire Indonesia west area at that moment. Keywords: MJO, RMM1 and RMM2, OLR, Power Spectral Density, ARIMA, Rainfall