Generally, most of the available ocean current information is based on in situ observational such as ship drift, drifting buoy or current metre, before satellite mission. However, this limited information reveals some important features of the ocean circulation. Since, the advance of space-based technology which is able to provide a global, high-resolution information, and regular monitoring of ocean, make possible to observe global ocean current and understanding the ocean circulation from space. For an area where there is no comprehensive in situ observational, satellite data become important data to investigate the sea surface current and circulation

This chapter reviews some of the important concepts and topics related with this study. There are four major sections in this chapter. The first part reviews the monsoon seasons at Malaysia, Northeast monsoon, Southwest monsoon and two inter monsoon seasons. The second highlights the previous study at the study area including the methods that are used and the results from previous study. Thirdly, discussions focus on background theory of sea surface current; wind-drift and geostrophic current.Finally, details concerning the satellite altimetry mission, concept of altimetry measurement, high-precision and high resolution are presented. Overview of Radar Altimeter Database System is also discussed in this section.