Impact of ENSO and IOD on chlorophyll-a concentration and sea surface temperature in the Bali Strait

Abstract

ENSO and IOD are oceanographic phenomena that occur in the tropical Pacific Ocean and Indian Ocean, due to the interaction between the sea and the atmosphere. The study aims to determine the impact of ENSO and IOD on the abundance of Sea Surface Chlorophyll (SSC) and Sea Surface Temperature (SST) in the Bali Strait. The data used are Ocean Nino Index (ONI), Dipole Mode Index (DMI), Sea Surface Chlorophyll (SSC) and Sea Surface Temperature (SST). The method applied the SSC and SST anomaly analysis during the ENSO and IOD periods from March 2000 to July 2020. The results showed that during the ENSO and IOD periods in the eastern monsoon, there was an increase in SSC concentrations and a decrease in SST in the Bali Strait. In the ENSO period, there were La Nina and El Nino phases, while IOD had positive and negative phases. During the observation, it was known that the mean range of SSC was 0.49 - 1.91 mg m-3 and 25.32 - 29.30 °C for SST. SSC anomaly during the observation period was between -0.04 - 0.62 and SST was -0.66 - 1.47. Therefore, it was known that the period that causes an increase in high SSC and a decrease in SST in the waters of the Bali Strait was during the El Niño period along with positive IOD phases in 2006, 2015, 2018, and 2019.