ANALYSIS OF VORTEX IN EASTERN INDIAN OCEAN USING POTENTIAL VORTICITY

• Main Author: Putri Damayanti, Riggita
• Format: Final Project
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/38758
• Institution: Institut Teknologi Bandung

A significant phenomenon influencing wind circulation in Indonesia is the vortex phenomenon. Vortex is defined as a flow that has vorticity. Vortex is often studied, namely Borneo Vortex, but there are other vortex that develop besides Borneo Vortex whose presence is often associated with extreme events. But the formation and intensification of the vortex has not been studied further. Analysis of the development of this vortex can be explained by potential vorticity. This study analyzes the evolution and reinforcement of vortex phenomena in the Southern Hemisphere using potential vorticity. The study area in this study is Eastern Indian Ocean and the time of study began in 1998/1999 to 2015/2016 in the period of December-January-February. The vortex phenomenon was identified using ECMWF (European Center for Medium-Range Weather Forecast) ERA-Interim Reanalysis data. This phenomenon identified as daily event. The stage of identifying vortex phenomena uses streamline and relative vorticity. While the analysis of its formation is carried out using the vortex system using potential vorticity in the isentropic layer. The results of this study shows that 84 systems with three different movement characteristics occurred in 295 days of events during the study period. Composite analysis of potential vorticity anomalies shows that the initial formation of vorticity in the Eastern Indian Ocean is associated with the appearance of negative anomalies of potential vorticity from the west. The advection of negative anomalies of potential vorticity from the west which causes the formation of potential vorticity anomalies and reinforcement of anomalies becomes increasingly negative to form a cycloneic pattern which is subsequently identified as vortex.