STUDY OF HEAT TRANSPORT AND OCEAN HEAT CONTENT FLUCTUATIONS ON TROPICAL CYCLONE EVENTS IN THE BANDA SEA (CASE STUDY: 2019-2019)

• Main Author: Rizki Pratama, Khafid
• Format: Theses
• Language: Indonesia
• Subjects: Ilmu kebumian
• Online Access: https://digilib.itb.ac.id/gdl/view/76984
• Institution: Institut Teknologi Bandung

This study aims to determine heat transport fluctuations in the Indonesian Throughflow (ITF) that have an impact on changes in the ocean heat content and their relation to the tropical cyclones in the Banda Sea over the 2009–2019 period. The analysis uses the Copernicus Marine Environment Monitoring Service (CMEMS) reanalysis data involving meridional current components in the ITF Line, namely the Makassar Strait and the Lifamatola Strait. During El Niño, meridional currents and ITF transport with an average depth of 0-300 meters experience a weakening, while during La Niña, they tend to strengthen. In terms of the vertical profile, heat transport in the Makassar Strait during La Niña was detected to be stronger in the Labani Channel and near the coast of Central Sulawesi, with values of 1.2 PW and 0.6 PW, respectively. The Lifamatola Strait was identified as strengthening in the Lifamatola Channel and the Halmahera Strait with a value of 0.5 PW and 0.3 PW, respectively. The results of the lag correlation between heat transport and the Oceanic Niño Index (ONI) show that the time lag during El Niño (La Niña) is around 7-8 (3–4) months. The correlation between the heat transport in the two straits and the ocean heat content in the Banda Sea results in a time lag of 3–4 months. Processing using the Empirical Orthogonal Function (EOF) for ocean heat content (OHC), sea surface temperature (SST), sea surface height (SSH), and mixed layer depth (MLD) produces the first mode variance of 64, 2%, 77.9%, 91.7%, and 58.9% and shows an inverse relationship with the ONI index. Meanwhile, the salinity produces a first-mode variance of 59.6% with a relationship that is directly proportional to the ONI index. It was identified that the OHC increased along with the strengthening of heat transport due to the strengthening of ITF transport. During El Niño (La Niña) causing SSH elevation to decrease (increase), ITF transport and heat transport to weaken (strengthen), and OHC to decrease (increase). The intensity of tropical cyclone events shows that there are differences related to fluctuations in heat transport and ITF transport. The maximum OHC in the Banda Sea occurs in March, April, and May. The characteristics of a strong tropical cyclone in category 1 with a short duration of movement are affected by an increase in OHC. In contrast, long-duration tropical depressions (TD) are affected by decreasing OHC. TD and tropical cyclone events in the Banda Sea have v been identified to occur along 5°S to 6°S. However, the characteristic of tropical cyclone phases in the Banda Sea can be identified with long period of the dataset.