Exploration on Coral Reef Resources, Using Glint Removal and Depth Attenuation Index on Alos Imagery at Biak Island, Papua, Indonesia

Abstract

The coral reef resources at Biak Island have been identified and studied through ground truth carried out during July 2007 and Alos imagery analysis with 10 m resolution recorded on 25 May 2010, it is assumed that there is no change for 3 years. The study integrates the 59 field data into Alos image data, using glint removal and depth invariant index algorithms to generate coral reef ecosystem classes. Those classes are: live corals, dead corals, a mixture of both, and sand The algorithm that is composed of three visible bands is applicable at clear water rather than at turbid water environment. Hence, vegetation coverage as well as seagrass, seaweed, and macroalgae which are to a small extent and usually covered by fine sand materials and associated with turbid water, are neglected. Corals at Biak Island spatially at Northeast part which is facing directly towards the Pacific Ocean is narrow, 50 to 150 m wide, covers an area of 1031 ha., live corals dominated 38 ha. (3%) and at Southwest part is 50 – 700 m wide, covers an area of 2161 ha., live corals dominated occupies 215 ha. (9%). It is suggested that the strong waves from the Pacific Ocean will cause corals in the North does not to thrive. This research aims to produce a map of the coral reef ecosystem at Biak Island, Indonesia, reached from 135^o48’E - 136^o28’E; 0^o41’S - 1^o15’S.