Shadow Zone Analysis in Banda Sea Region Based on Profiling Float Data

The Banda Sea is an essential part of the Indonesian Archipelago Sea Lane (ALKI) III, which is strategic but still minimally explored. The crucial position of the Banda Sea in international shipping lanes and maritime defense operations requires a more in-depth oceanographic study related to underwater defense strategies. In this study, the Arvor I profiling float operated by BMKG provides real-time data with Iridium satellite communication to observe oceanographic parameters such as temperature, salinity, and depth. This study aims to analyze the shadow zone, which has essential implications for underwater acoustic operations, especially submarine navigation. The research methodology includes analysis of vertical temperature and salinity profiles to identify the thermocline layer. The speed of sound is calculated using the McKenzie equation by considering variations in temperature, salinity, and sea depth. Acoustic propagation simulations were performed using the spherical spreading model approach to map the distribution of the shadow zone. The analysis results indicate the presence of a thermocline at a depth range of 44.7 to 1016.4 meters, with a minimum point of sound speed at a depth of around 992 meters. Understanding the distribution of this shadow zone can significantly contribute to the optimization of underwater acoustic operations in the Banda Sea region, including in supporting submarine operations and other acoustic monitoring activities.