VARIATIONS IN EXTREME RAINFALL IN INDONESIA ASSOCIATED WITH FOUR PROPAGATION TYPES OF MADDEN-JULIAN OSCILLATION B

• Main Author: Setiabudi, Dendi
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/85250
• Institution: Institut Teknologi Bandung

The MJO phases have different characteristics and influences from each other in Indonesia. The impact of the MJO on extreme daily rainfall (???????????????? ? ????????), namely the 95th extreme, is known by quantifying the difference in probability of extreme daily rainfall during the MJO phases versus NDJFMA (? ????????????????). MJO has four propagation characteristics (stand, jump, fast, and slow). In this study, the difference in the 95th extreme probability is the impact of the characteristics of each type of MJO propagation which are different from each other. MJO identification is by using a band-pass filter frequency of 20-70 days against the daily average Outgoing Longwave Radiation (OLR) and certain criteria. MJOs identified according to certain criteria from the band-pass filter will be grouped based on the similarity of propagation types using the k-mean clustering method. In addition, a regional probability matrix of the 95th extreme probability difference is created. The difference in daily rainfall and the probability of the 95th extreme follows the propagation of the active and inactive phases of each MJO type. Active phases 2-4 from slow and fast from the Indian Ocean to Indonesian territory (inactive phases 6-8) followed by an increase (decrease) in daily rainfall of 6 mm (-6 mm) and a probability of the 95th extreme of 67 -100% (-67 to -100%). The active phase and inactive phases of jump and stand do not propagate through Indonesian territory, but their active phases (inactive phases) approach Indonesian territory and cause an increase (decrease) in daily rainfall of 4 mm (-6 mm) and an increase (decrease) 95th extreme probability of 34-67% (-67 to -100%). Meanwhile, the regional probability of a positive 95th extreme probability difference or positive probability (negative probability) also has the same or follows the propagation of active phases (inactive phases) for each MJO type from west to east, just like the similarity of the pattern of bulk differences daily rainfall and 95th extreme probability.