Sains Malaysiana 36(2):  165-173 (2007)

Current Circulation Pattern in Waters

around Pulau Tinggi, Johor

(Corak Peredaran Arus di Perairan Pulau Tinggi, Johor)

Fredolin T. Tangang, Mohd Syamil Mohd Yussof & Liew Juneng

Marine Science Program

School of Environmental and Natural Resource Sciences

Faculty of Science and Technology

Universiti Kebangsaan Malaysia

43600 UKM Bangi, Selangor, Malaysia

Received: 15 October 2005 / Accepted: 17 April 2007

ABSTRACT

The current circulation pattern in waters around Pulau Tinggi, Johor was deduced based on the results of the Acoustic Doppler Current Profiler (ADCP) measurements during a period of 16 – 19 August 2004. It appears that the currents, regardless of tidal cycle, were predominantly southerly or southeasterly with average speeds of between 30 – 50 cm s^-1. There appears to be current speed horizontal gradient toward the island as the current became weaker as it gets closer to the island. In the upper 10-15 m the currents were slowed by the prevailing winds which were predominantly southeasterly during the period. In the lower layer, about 10 m from seabed, the current speed reduced drastically due to bottom friction. The circulation pattern proves to be a typical pattern of a flow around an island where an evident of an eddy was captured in the observation data in a station located south of the island. Estimated shallow water Reynolds number indicates that the flow may produce a pair vortex of opposite direction and a central return flow at the southern end of the island.

Keywords: Pulau Tinggi; current circulation pattern; tides; island wake

ABSTRAK

Corak peredaran arus di perairan Pulau Tinggi Johor telah disimpulkan berdasarkan hasil pengukuran arus menggunakan Acoustic Doppler Current Profiler (ADCP) bagi tempoh dari 16 hingga 19 Ogos 2004. Didapati corak arus, tanpa mengira fasa pasang-surut, adalah mengarah ke selatan atau tenggara dengan purata kelajuan antara 30 – 50 cm s^-1. Terdapat kecerunan mendatar kelajuan arus ke arah pulau di mana arus menjadi semakin lemah apabila menghampiri pulau. Di lapisan atas iaitu pada kedalaman 10-15 m, arus diperlahankan oleh tiupan angin yang dominan ke arah tenggara pada tempoh tersebut. Di lapisan bawah, lebih kurang 10 m dari dasar kelajuan arus menurun secara mendadak akibat geseran dasar. Corak perederan yang diperolehi adalah corak yang biasa bagi aliran mengelilingi pulau dengan cerapan menunjukkan terdapat pusaran di stesen bahagian selatan pulau. Anggaran nombor Reynolds menunjukkan aliran mungkin menghasilkan satu pasangan vorteks yang bertentangan arah dan satu aliran kembali di hujung bahagian selatan pulau ini.

Kata kunci: Pulau Tinggi; corak peredaran arus; pasang surut; keracak pulau

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