Ocean Net Primary Productivity Response to Seasonal and Interannual Climate Variability in the Southern East Java and East Nusa Tenggara Sea Region Muhammad Firman Nuruddin (1,2)- Mutiara Rachmat Putri*1
1. Department of Oceanography
Faculty of Earth Sciences and Technology
Bandung Institute of Technology
2. Ocean Science Department, School of Science, The Hong Kong University of Science and Technology
Abstract
The dynamics of ocean net primary productivity (NPP) in the Indonesian ocean are influenced by seasonal climate phenomena, monsoon trade wind, and inter-annual extreme variations, El-Nino Southern Oscillation (ENSO), as well as Indian Ocean Dipole (IOD). However, these complex interactions are still rarely explored in Southern Indonesian Sea areas. In this study, we use the NPP data from NEMO3.6-Pisces v2 model results, wind speed, and climate variability index (Dipole Mode (DMI) and Ocean Nino Index (ONI)) to elucidate the spatiotemporal variability of NPP along the Southern East Java and East Nusa Tenggara Sea region during the 1998 until 2018 period. Our analysis found that seasonal variation of NPP corresponded with the seasonal upwelling (downwelling) phenomena which happened during south (north) east monsoon period with the average magnitude of NPP varying between 339.30 and 567.20 mgCm-2day-1. Meanwhile, the climatological anomaly of the NPP in this region is more influenced by the interannual extreme event of the Indian Ocean Dipole compared to El-Nino Southern Oscillation as shown by the partial correlation value between NPP and DMI (ONI) 0.56 (0.28). Specifically, when IOD+ (-) occurred, there was positive (negative) increment on the ocean productivity anomaly. This study reveals an important relationship between annual-interannual climate phenomena and ocean primary production variability in a complex ocean region.
Keywords: Net primary productivity, Monsoon, ENSO, IOD
