Long-term trend and variability of ocean heat content in the Indonesian Maritime Continent

Abstract

The evolution of 64 years of the ocean heat content for the upper 300 meters (OHC300) in the Indonesian Maritime Continent, viz the Banda Sea, the Sulu Sea, the Java Sea, and the Karimata Strait, was investigated using the combination of ocean and atmosphere reanalysis data. The study aims to understand its long-term trend variability and association with El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). The result showed a positive trend in all basins except the Banda Sea. The most significant rise was the Sulu Sea. The IOD fluctuation was more pronounced in the Western part of Indonesia. In contrast, the ENSO variation was more apparent in the Eastern part of Indonesia. The coincided La Nina events and the negative IOD significantly increased OHC—conversely, the coinciding of the El Niño events and the positive IOD caused a decrease in OHC magnitude. The significant factor increasing OHC in the maritime continent is the ENSO fluctuation, followed by the IOD fluctuation.