to adequately image through a water column and to delineate variation in coral reef ecosystem benthic types, sensors having high spatial, e.g., a cirrus digital camera system (dcs), and spectral, e.g., the airborne visible infrared imaging spectrometer (aviris), resolution and high signal to noise are needed. further, there is a need to better understand the optical properties of coral reefs, seagrass, other benthic types, and water column constituents from field-collected data so current and future remote sensing can be optimized for coastal zone ecosystem research and management. in august 2004, we flew the aviris and dcs on a nasa er-2 over the florida keys and puerto rico. in march 2005, we flew aviris/dcs on the twin otter over kaneohe bay, oahu. also, in december 2005, we flew aviris/dcs on the twin otter over puerto rico and the us virgin islands for assessment of the 2005 caribbean coral reef bleaching event. for each of these deployments, we collected coincident spectral data from dominant bottom types and coral under various health conditions using a hand-held spectroradiometer. these spectral data will be used to classify the benthic types within the aviris imagery. an overview of the airborne missions and coincident field data collection will be presented along with preliminary image and field-collected spectral data products.
the photosynthetic pigments of coral’s symbiotic algae (zooxanthellae) and the general establishment of corals in shallow well-lit waters enables the detection of spectral information from coral through a clear shallow water column with a remote sensing instrument. corals display distinct reflectance peaks between 550 and 650nm related to the densities of chlorophyll-a and accessory pigments in their tissue (holdren and ledrew, 1998; myers et al., 1999; hochberg and atkinson, 2000; hochberg et al., 2003). research has shown that spectral distinction of reef bottom types (i.e., coral, algae, and carbonate sand) is possible using field spectroscopy (clark et al, 2000; hochberg and atkinson, 2000; andrefouet et al., 2001; lubin et al., 2001; hochberg et al., 2003; wettle et al., 2003). of further interest is the identification of spectral features indicative of degradation in reefs which could lead to better ecological assessment (e.g., biodiversity) and forecasting (call et al., 2003; hochberg et al., 2003).