ANALYSIS OF EL-NINO SOUTHERN OSCILLATION (ENSO) AND INDIAN OCEAN DIPOLE (IOD) SIGNALS IN OCEAN AND WATER MASSES HEAT CONTENT AT EASTERN INDONESIA SEA

• Main Author: Lazuardi Ramadhan, Fauzan
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/50005
• Institution: Institut Teknologi Bandung

The inter-annual climate phenomena influence the Indonesian Sea conditions, particularly in Eastern Indonesian Sea. As the Indonesian Throughflow (ITF) pathway, these waters will be affected by the phenomenon of El-Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD, similarly to the ocean and water mas heat content. This study aims to determine the effect of climate phenomena on ocean and water masses heat content at the study location. The data used in this study is salinity and temperature data derived from the HYbrid Coordinate Ocean Model (HYCOM) reanalysis model. Cross Wavelet Transform (XWT) and Coherence Wavelet Transform (CWT) analyzes are used to analyze the relationship of water mass heat content, while the Empirical Orthogonal Function (EOF) analysis is utilized to analyze the relationship of ocean heat content with ENSO and IOD phenomena. The contribution of water mass heat content in the Makassar Strait, Banda Sea, and Timor Sea is dominated by West North Pacific Central Water (51,23%), Banda Intermediate Water (32,36%), and Indonesian Upper Water (31,80%). Based on XWT and CWT analysis, the water mass heat content in the mixed and depth layer will decrease (increase) when the El-Niño or IOD Positive (La-Niña or IOD Negative), while for the same water mass at the different study location in the thermocline and intermediate layer has a different response to ENSO and IOD phenomenon. Based on EOF analysis, ENSO (IOD) explains about 75,5% (9,52%); 91,99%; and 88,66% with 2 (8), 1, and 1 month lags in the mixed layer (0 – 80 m), thermocline layer (80 – 400 m), and depth layer (400 – 5000 m) of the total anomalous Eastern Indonesian Sea ocean heat content variation.