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Sobri Effendy
Departemen Geofisika dan Meteorologi, FMIPA-IPB

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PENGEMBANGAN MODEL PREDIKSI MADDEN JULIAN OSCILLATION (MJO) BERBASIS PADA HASIL ANALISIS DATA REAL TIME MULTIVARIATE MJO (RMM1 DAN RMM2) (PREDICTION MODEL DEVELOPMENT MADDEN JULIAN OSCILLATION (MJO) BASED ON THE RESULTS OF DATA ANALYSIS ... Lisa Evana; Sobri Effendy; Eddy Hermawan
Agromet Vol. 22 No. 2 (2008): December 2008
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (829.212 KB) | DOI: 10.29244/j.agromet.22.2.144-159

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 Maret 1979–1 Maret 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 Zt = Zt = 1,681 Zt-1 – 0,722 Zt-2 - 0,02 at-1 - 0,05 at-2.. Prediction model for RMM2 is Zt = 1,714 Zt-1 – 0,764 Zt-2 - 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.
PEMANFATAAN DATA EQUATORIAL ATMOSPHERE RADAR (EAR) DALAM MENGKAJI TERJADINYA MONSUN DI KAWASAN BARAT INDONESIA(THE VALUABLE OF EQUATORIAL ATMOSPHERE RADAR (EAR) DATA TO STUDY MONSOON IN THE WEST AREA INDONESIA) Veza Azteria; Sobri Effendy; Eddy Hermawan
Agromet Vol. 22 No. 2 (2008): December 2008
Publisher : PERHIMPI (Indonesian Association of Agricultural Meteorology)

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (992.783 KB) | DOI: 10.29244/j.agromet.22.2.160-173

Abstract

Kototabang, Padang Panjang and Sicincin city are area in the West part of Indonesia and they are relative in the equator line. Otherwise, three of these cities have difference of behaviors of rainfall for Monsoon. In this study, we were used EAR Data, which were including the rainfall Kototabang, Padangpanjang, and Sicincin. Base on this data (i.e EAR data) in Kototabang, there is monsoon in 8-18 km layer and the higher monsoon is in 14 km layer during the April 2002-April 2006 period. Analisis Power Spectral Density (PSD) and Transformasi wavelet were shown that Monsoon oscillation around 12 months. While vertical profile was presented that the stronger monsoon will be in the wet weather on January. The domination of wind in Kototabang city is South Wind, it is because the wind took water vapor mass from South to North. According to analysis of rainfall in Kototabang, Padangpanjang and Sicincin City, meridional wind in the the Sicincin has rainfall pattern the same as with monsoon. Its was indicated that there were local indicator which can cause the monsoon. From the cross correlation between meridionial wind speed with rainfall in Kototabang, Pontianak and Sicincin, they were shown that three of these cities have significant correlation.