Geoscience Reference
In-Depth Information
Seasonal Sea Surface Circulation
in the Northwest Region Off the Borneo
Island Based on Nineteen Years Satellite
Altimetry Data
Muhammad Faiz Pa'Suya, Kamaludin Mohd Omar, Benny N. Peter
and Ami Hassan Md Din
Abstract Seasonal variation of sea surface circulation in the northwest coast of
Borneo Island were illustrated using altimetry data provided by six missions of
satellite altimetry for the period of nineteen years (1993-2011). The estimated sea
level anomaly (SLA) from altimetry data using Radar Altimeter Database System
(RADS) is consistent with the tide gauge measurement at Kota Kinabalu and Bintulu.
The SLA is combined with the 1992-2002 Mean Dynamic Ocean Topography to
determine the absolute dynamic topography. Assuming geostrophic balance, the
geostrophic current is estimated from the absolute dynamic topography and mapped
for four specific months which represent the monsoon seasons; August (Southwest
Monsoon), December (Northeast Monsoon), April (inter-monsoon) and October
(inter-monsoon). The pattern of estimated surface current is consistent with the Argos-
tracked Drifting Buoy's track. In general, surface circulation in the central part of the
southern region of South China Sea during April, October and December is cyclonic.
Along the northwest coast of Borneo Island, the surface current is flowing north
eastward during all months except in August, when the current is flowing northward.
A few eddies have also been observed from the estimated surface current pattern.
Keywords Sea surface circulation
Monsoon
RADS
Borneo Island
Satellite
altimetry
