Environmental Engineering
Suhaemi .; D.G. Bengen; C.P.H. Simanjuntak; A.F. Koropitan
Abstract
BACKGROUND AND OBJECTIVES: The Misool Islands are lined up regularly from west to east, the southern part of Raja Ampat Archipelago, Papua - Indonesia. The geomorphology is distinctive, and the coral reef substrate causes turbulence. Misool waters are located in the Papuan bird's head seascape, passed ...
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BACKGROUND AND OBJECTIVES: The Misool Islands are lined up regularly from west to east, the southern part of Raja Ampat Archipelago, Papua - Indonesia. The geomorphology is distinctive, and the coral reef substrate causes turbulence. Misool waters are located in the Papuan bird's head seascape, passed by Pacific water masses. The assessment status of Misool waters as a conservation area does not include hydrodynamic aspects in the decision processes. The present study is fundamental for determining and changing essential areas for conservation. The main objective of this study is to the pattern of hydrodynamic processes and investigate the features of the water mass in the Misool waters.METHODS: An acoustic doppler current profiler was deployed to measure currents every 15 minutes for ten water column layers. Investigation of waters characteristics was using Conductivity-Temperature-Depth equipment. A three-dimensional computational model was performed using MIKE3.FINDINGS: The water mass around the Misool Islands are more influenced by the local oceanographic processes than the water masses from the Pacific Ocean. The study site is characterized by the mixed tide, prevalence to semi-diurnal based on observational tidal data. Wind and baroclinic properties generate non-significant currents, resulting in low horizontal and vertical stratification. Intensification of tidal currents occurs along the shallow part in northeastern and part of the channel between Misool Islands and the mainland of Papua.CONCLUSION: The interaction of barotropic tides, geomorphology, and coral reef triggers the unstratified water mass. Strong currents and turbulence on the northeast side produce homogeneous waters. The water mass in Misool waters is originated from the local dynamic.
Environmental Science
A.F. Koropitan; M.H.I. Khaldun; Y. Naulita
Abstract
BACKGROUND AND OBJECTIVES: The southeast Indian Ocean is one of the areas where tropical cyclones formed. A comprehensive understanding of the cyclone impact in the Southeastern Indian Ocean is needed to anticipate future changes due to the warming trend. The present study investigates the influence ...
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BACKGROUND AND OBJECTIVES: The southeast Indian Ocean is one of the areas where tropical cyclones formed. A comprehensive understanding of the cyclone impact in the Southeastern Indian Ocean is needed to anticipate future changes due to the warming trend. The present study investigates the influence of Cyclone Marcus on oceanographic processes in the subsurface and surface layers and its impact on temperature and Chlorophyll-a in the Southeastern Indian Ocean. The present study applies the Argo Float data located near the peak of the Cyclone Markus path and could capture the subsurface layer vertically that has never been reported previously.METHODS: This study performs Copernicus data set and Argo Float data to analyze the oceanographic feature of the region before, during, and after Cyclone Marcus.FINDINGS: The average surface current velocity increased almost two times during Cyclone Marcus, and the eddy was formed in the clockwise direction following the surface wind pattern. The Argo Float data presents that Cyclone Marcus could induce surface divergence (clockwise eddy) where the cold water and high salinity waters pumped up to the surface layer, starting 1 day after the peak of Cyclone Marcus, resulting in cooling surface temperature by 1.7 °C and deepening mixed layer depth up to 60 m. It implies that the lifted nutrient-rich water stays in the mixed layer depth for 11 days, and sea surface Chlorophyll-a concentration increase with time lags of 2.5 days and 5.6 days, respectively. The Chlorophyll-a concentration increases 2.5 times, and since then starts to decrease until its ‘normal concentration’ within two weeks.CONCLUSION: Cyclone Marcus triggers the entrainment between the subsurface layer and the sea surface, forcing a phytoplankton growth, particularly in the path area. The future cyclone could increase in the category in the study area, as the warming trend in the Indian Ocean.
