Dynamic of upwelling variability in southern Indonesia region revealed from satellite data: Role of ENSO and IOD

• Published in: Journal of sea research Vol. 202; p. 102543
• Main Authors: Rachman, Herlambang Aulia, Setiawati, Martiwi Diah, Hidayah, Zainul, Syah, Achmad Fachruddin, Nandika, Muhammad Rizki, Lumban-Gaol, Jonson, As-syakur, Abd. Rahman, Syamsudin, Fadli
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2024
• Subjects: Correlation; El Niño Southern Oscillation (ENSO); Indian Ocean Dipole (IOD); Satellite data; Southern Indonesia; Upwelling; Upwelling; Correlation; Indian Ocean Dipole (IOD); El Niño Southern Oscillation (ENSO); Satellite data; Southern Indonesia
• ISSN: 1385-1101
• DOI: 10.1016/j.seares.2024.102543

The Southern Indonesian (SI) region is known for its high-intensity coastal upwelling caused by monsoonal wind. Interannual phenomena such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) also influence upwelling activity in this region. This study analyzed the relationship between upwelling intensity (UIsst) and those variables and their impact on oceanographic features such as Sea Surface Temperature (SST) and chlorophyll-a concentration. We used satellite imagery data, including SST from the National Oceanic and Atmospheric Administration (NOAA) and chlorophyll-a from MODIS, to analyze the aforementioned issue. To identify the impact of wind patterns on coastal upwelling, we analyzed using zonal wind stress from ERA-5 Data. Quantification of UIsst is defined as the SST gradient between the coastal and open ocean waters. Linear and partial correlation analysis between UIsst with the Ocean Niño Index (ONI) and Dipole Mode Index (DMI) were conducted to see the influence of ENSO and IOD phenomena. Anomaly analysis was also conducted on SST, chlorophyll-a concentration, zonal windstress and UIsst to see how large the values were during the years of the ENSO and IOD events. Upwelling in the SI region typically occurs during southeast monsoon (SEM) periods, starting earlier in the East side (Nusa Tenggara Islands) and moving towards the West side (South Coast of Java). The correlation analysis (both linear and partial) indicates that the IOD has a stronger influence on UIsst in the SI region compared to ENSO, especially during June to October (SEM periods). This finding is confirmed by anomaly analysis, which reveals significant changes in SST, chlorophyll-a concentration, zonal windstress, and UIsst during ENSO and IOD events. The magnitude of the anomalies is generally stronger during IOD events than those observed under ENSO conditions. •Remote sensing satellite data can identify the variability of upwelling phenomena in the Southern Indonesian (SI) seas.•The strength of upwelling intensity in SI is strongly influenced by Interannual phenomena such as the ENSO and IOD.•Sea Surface Temperature and Chlorophyll-a anomalies confirm the influence of changes in upwelling intensity by ENSO and IOD.•IOD has a stronger influence than ENSO on Upwelling intensity in the SI Region.