Shift Of The Annual And Semi-Annual Oscillation Of The Rainfall Over Indonesia Maritime Continent

Climatology of rainfall data over Indonesia maritime Continent (IMC) showed three types of rainfall: Annual Oscillation (AO), Semi-Annual Oscillation (SAO), and local rainfall which is defined as opposite pattern of AO. Shift of the AO and SAO of rainfall over IMC was investigated using 10 years of near surface rainfall data based on Satellite TRMM 2A25 using least square method. The results showed that AO was identified in Java, Bali, Nusa Tenggara, Aceh, eastern Papua, and central Kalimantan. Meanwhile, SAO were confirmed in Padang, Lampung, western and eastern Kalimantan, and western Papua. Interestingly, most of the rainfall in Sumatra and Kalimantan are not included in AO and SAO. Whereas rainfall in Sulawesi included both of AO and SAO. Halmahera and Northern Maluku were categoried as an AO, whereas Seram island and Maluku included of the SAO. In addition, the results also showed that large parts of IMC have a phase change in the AO and the SAO, except for the southern part of Sumatra, Borneo, and northern PapuaHlm.7-1