Study of driving force and surface current patterns in Labuan Bajo from High Frequency Radar Data in October-December 2018
Yustika Baharsyah (a*), Aradea R. Hakim (b), Andri Ramdhani (b), Rima Rachamayani (b)

Oceanography, Bandung Institute of Technology
Jalan Ganesha 10, Bandung 40132, Indonesia

Abstract

Surface current data was processed in Labuan Bajo from October to December 2018 to analyse them spatially and temporally and to determine the driving force of surface currents. The current data set is derived from measurements of High Frequency (HF) radar, which operates on the electromagnetic wave spectrum at high frequency or short wave. The average wind speed over three months is 4.39 m/s, with winds primarily from the north and northeast, with the west monsoon strengthening and the east monsoon weakening. With a semidiurnal tidal type, the average elevation value for three months is 1.52 meters. The study area demonstrates that shallow waters have currents that move southward or approach the island of Komodo at irregular speeds, influenced by small islands. Because of the deep bathymetry, the current moves to the west following the wind direction, at a constant speed. The direction of the current indicates that the tides influence current movement in shallow water, whereas the wind influences current movement offshore. The correlation and filtering results show that the influence of tides is greater than the influence of wind at each review point. However, the wind^s influence remains strong, particularly offshore. EOF mode 1 has a variance of 56.2% because of tides, mode 2 has a variance of 26.6% because of bi-weekly variability, and mode 3 has a variance of 17.2% because of the intra-seasonal period.

Keywords: Surface current- HF radar- wind, tide- filtering- FFT- Correlation- EOF

Topic: Ocean Sciences