TROPICAL COASTAL ENGINEERING IN INDONESIA ADAPTING TO NEAR-TERM OCEAN-CLIMATE CHANGES

Bali Coastal Experimental Station, Public Works of ROI is seeking Tropical Coastal Engineering (TCE) in Indonesia. As a near-term perspective of ocean climate changes in the western tropical Pacific, there are three major effects concerning to TCE. One is the decadal oscillation of North Pacific Ocean (PDO) that is related to long-term changes in ENSO, such as La Nina dominant and El Nino dominant periods. Based on multivariate ENSO index (MEI), it is indicated that El Nino dominant period may shift to La Nina dominant around 2007 that will increase rainfall in the Indonesian archipelago. The second one is lunar nodal tide of 18.6 year period. In 2007, an extreme flood modulated by coastal tide occurred in Jakarta and some coastline cities in Indonesia. Its next peak is expected in 2025. Heavy rainfalls caused by El Nino dominant period and the peak of lunar nodal tide may cause the estuary flooding in the next 25 years. The third effect is the changes in solar activities. Observations of "Sunrise", a solar observation satellite in January 2012, found that the solar magnetic field becomes "quadrupole structure" that may reduce solar energy and increase of galaxlian cosmic ray resulting in increase of cloud cover especially in the Inter-Tropical Convergence Zone (ITCZ). This effect could trigger a mini-Ice Age on Earth with increasing of precipitation in the tropical area. An increase of flooding may cause the increase of sediment transport from the river. TCE should solve these challenges of coastal and estuary problems in Indonesia. This paper summarizes these effects in Indonesian costs and perspectives of TCE.