This research examines ocean conditions in the Indonesian seas, a key area linking the Pacific and Indian Oceans. We analyzed two centuries of direct ocean measurements and found large gaps in deep-sea and coastal data that limit climate and marine studies. We suggest better monitoring, technology, and collaboration to improve understanding of ocean changes. These efforts will help predict climate impacts and support marine conservation and sustainable resource use.

Our research evaluated the precision of mapping the ocean's surface with combined data from a couple of satellites, focusing on dynamic aspects revealed by sea level changes. Results show that 2DVAR, a new mapping product, aligns more closely and with less error with the most advanced satellite detailed observations than a widely used mapping product called AVISO. The results suggest that 2DVAR better detects minor ocean movements, making it more valuable and reliable for ocean dynamics study.

We provide new insights on the presence of oxygen-depleted waters along the Indonesian coasts of Sumatra and Java attributed to the eastward advection of the northern Indian Ocean waters and monsoon-driven upwelling. Combined in situ and reanalysis data elucidate the complex interplay of oceanographic processes responsible for the observed oxygen in the region. The knowledge is crucial for research and management strategies to mitigate deoxygenation impacts on marine ecosystems in Indonesia.

The JES is a mid-latitude “Miniature Ocean” featured by multiscale oceanic dynamical processes and sea ice, which strongly influence the JES SSC. However, the dominant factors that favor and/or restrict SSC and how they influence JES SSC on different time scales are not clear. In this study, these issues are investigated using EOF and PCA methods based on high-resolution satellite-derived SSC data provided by the Copernicus Marine Environment Monitoring Service (CMEMS).

The Korea Strait is a major navigation passage linking the Japan Sea to the East China Sea and Yellow Sea. This paper establishes a theoretical model for the tides in the Korea Strait and Japan Sea using the extended Taylor method. The model solution explains the formation mechanism of the tidal amphidromic systems in the Korea Strait, and why the K₁ amphidromic point is located farther away from the shelf break separating the Korea Strait and Japan Sea in comparison to the M₂ amphidromic point.