Horizontal Structure of Banda Eddies and The Relationship to Chlorophyll-a During South East Monsoon in Normal and ENSO Period on 2008-2010

Abstract

Banda Sea is part of Indonesia Fisheries Management Area (WPP 714) which famous for Tuna fisheries. In addition to being influenced by Indonesian Through Flow (ITF), the Banda Sea also influenced by eddies. Banda eddies and the relationship to chlorophyll-a were studied by using the output of ocean circulation model produced by INDESO (Infrastructure Development of Space Oceanography) project in Ministry of Marine Affair and Fisheries. Data from 2008 to 2011 during normal phase of South East Monsoon period (June-August 2008), El Nino phase (June-August 2009), and La Nina phase (June-August 2010) were used. The model results showed two clockwise eddies in the northern of Banda Sea and three counterclockwise eddies in the southern of Banda Sea. The clockwise eddies were found at 20 meter depth and induced upwelling in south water of Buru Island, Ambon Island and Lease Island (Haruku, Saparua and Nusalaut Islands). Otherwise, counterclockwise eddies in the southern of Banda Sea (north of Wetar Island and Yamdena Island) generate the downwelling. High vorticity value of the eddy was found in the northern of Wetar Island. The presence of Banda Eddies on South East Monsoon period play an important role to maintain the water mass balance in the Banda Sea. Eddies also have strong influence on nutrient sinking from the surface of water. In addition, the eddies vorticity increased during the La Nina period and lead to low surface chlorophyll-a in the surface of the Banda Sea.

Simulated ocean circulation and its variability in the Northern Banda Sea from CROCO model

“…Previous studies have investigated the influence of ENSO and IOD on the spatial distribution of SST and chlorophyll-a [12], the vertical structure and variability of the ITF flowing into the western edge of the Banda Sea [13], the horizontal structure of eddies in the Banda and their relationship to chlorophyll-a during the 2008-2010 southeast monsoon in normal and ENSO periods [14], ENSO-influenced ITF transport [15], changes in surface circulation patterns during the 2008/2009, 2009/2010, and 2010/2011 "normal" events with implications for the Ekman layer and upwelling intensity [16], and research on the relationship of ENSO and IOD to SST and chlorophyll-a in the Banda Sea and the southern coast of Java, concluding that these phenomena have an influence on SST and chlorophyll-a variability [17]. However, no one has studied the variance and variability of each oceanographic parameter, such as SST, seawater temperature, SSH, salinity, zonal, and meridional current components, and their relationship with ENSO and IOD phenomena with the time series until 2022.…”

Ocean Circulation and Variability in the Seram and Northern Banda Seas

“…Previous research has focused primarily on the circulation and stratification within the Banda Sea [11,12] with respect to the ITFs [8,13,14], with more emphasis on the western ITF compared to the eastern pathway that connects directly to the Seram Sea [15]. Research on the Banda Sea circulation model has also been conducted [16,17], which shows that ITF affects the variation of oceanographic parameters and the monsoon winds affect the complexity of the waters.…”

An Evaluation of a 1/18o Resolution Regional Ocean Circulation Model of CROCO in the Southern Sunda Shelf

“…Ocean modelling has long been used to study ocean dynamics and water mass stratification (Tranchant et al, 2016); and to analyze oceanographic phenomena, such as fronts (Ismail and Ribbe, 2019), upwelling (Kok et al, 2017), eddies (Horhoruw et al, 2020), barotropic and baroclinic tides (Koropitan and Ikeda, 2008;Nugroho et al, 2018;Katavouta et al, 2022), and ocean current systems (Tozuka et al, 2009;Susanto et al, 2012;Wei et al, 2016). Some benefits of using ocean modelling are as tools to better understand and to evaluate the physical processes and dynamics of ocean phenomena, which could contribute to the enhancement of our knowledge in the field of marine science and technology.…”