Seasonal and Interannual Variability of Particulate Organic Carbon in the Banda Sea

Abstract

The Banda Sea is the center of the global “Coral Triangle” characterized by high productivity. As the “mix master” of Indonesian throughflow and part of the Indo-Pacific Warm Pool, the Banda Sea is sensitive to climate variability events. However, few studies has been focused on seasonal and interannual variability and control mechanism of surface particulate organic carbon (POC) in the Banda Sea. Using 19 years of satellite data (2003–2021), this study analyzes the spatial and temporal variability of surface POC. A self-organizing map was applied to analyze interannual anomalies. The POC time-series follows a bimodal seasonal cycle, primarily driven by monsoon-controlled upwelling and surface currents. Concentrations of POC are higher in the east during the southeast monsoon (SEM), controlled by the eastern upwelling driven by the southeastwardly wind. POC concentrations are highest in the southwest during the northwest monsoon (NWM), influenced by the South China Sea throughflow. The interannual anomalies in the Banda Sea are controlled mainly by the El Niño-Southern Oscillation (ENSO) and the Indian Ocean Dipole (IOD). During +IOD/El Niño, the POC anomaly was positive during SEM, and the POC anomaly was negative during NWM; the reverse occurs during −IOD/La Niña. Excessive precipitation during the multiyear La Niña from 2010 to 2013 led to negative POC anomaly. The 2009–2010 El Niño Modoki caused westerly wind anomaly over the Banda Sea, resulting in opposite situation to the traditional El Niño. This study explores the remote control mechanism of surface POC in the Banda Sea by climate variability events.