Analisis Variabilitas Curah Hujan Indonesia pada Kejadian ENSO

Abstract

Indonesia is one of the countries which experiences El Niño and Southern Oscillation (ENSO) impact on rainfall variability. The purpose of this study included to investigate the Indonesian climate variations related to ENSO events and to understand the effect of ENSO on rainfall temporal distributions at Indramayu (6.35°LS, 108.32°BT) and Tabing (0.88°LS, 100.35°BT). Composite analysis method was used to reveal the trend of sea surface temperature anomaly, wind at 850 hPa, OLR and TRMM 3B43 rainfall data, whereas temporal and correlation analysis was used to observe rainfall and nino-3.4 index. When El Niño sea surface temperature anomaly (ASPL) maximum in October-December, 850 hPa wind backwards from west to east along with increased speed and deviation of OLR below the average values in central and eastern equatorial Pacific which indicates the accumulation of rain cloud. La Niña occurrence is indicated by the deviations of sea surface temperature below average. Low pressure center in Asia reached 850 hPa winds and strengthened Walker circulation, the movement of the air mass brought moisture to Indonesia. Based on the composite of TRMM rainfall, it appeared that the El Niño events gave more significant impact at the end of the year (October to December) on East Indonesia, Java and parts of Sumatra and Kalimantan, while La Niña (December to February) in south and eastern part of Indonesia. Monsoonal pattern (Indramayu) showed ENSO impacts more strongly than equatorial (Tabing). The shift of dry season and low rainfall were affected by ASPL fluctuations on nino-3.4 region.