ACQUISITION OF UNDERWATER REFLECTANCE MEASUREMENTS AS GROUND TRUTH

Work is being performed to establish effective quantitative methods for the mapping, monitoring and assessment of coral reef ecosystems using hyperspectral remote sensing. Specifically, imagery acquired over the Hawaiian Islands by NASA’s Airborne Visible InfraRed Imaging Spectrometer (AVIRIS) is being used to develop, apply and evaluate algorithms for analyzing coral reefs using airborne hyperspectral data. The imagery was obtained during two separate AVIRIS deployments to Hawaii, one in April 2000 and another in October 2001. The coral ecosystems covered in these deployments exhibit conditions ranging from significantly human impacted reefs in the Main Hawaiian Islands to the relatively pristine coral environments of the Northwestern Islands. In addition to this significant spatial coverage, the deployments also provide temporal coverage through repeat acquisition of select study areas. Of these locations, the primary study area being used for this research is Kaneohe Bay on the windward shore of Oahu (Figure 1). This area provides many advantages as a model system for developing algorithms, including ease of accessibility for fieldwork, a wealth of supporting research literature and limited species diversity. The bay also exhibits a significant range in habitat health, from coraldominated to algae-dominated, thereby allowing evaluations of algorithm effectiveness in identifying such differences.