Hyperspectral remote sensing in coastal regions: Prism field validation in Elkhorn Slough

Abstract

Hyperspectral imagery has been shown to be useful in monitoring and mapping coastal benthic habitats, yet many coastal areas remain challenging due to factors such as high turbidity and variability over fine spatial scales. The estuarine waters of Elkhorn Slough terminating in Monterey Bay, California present an excellent study site for testing the limits of hyperspectral imaging spectroscopy in a region with turbid sediment-laden waters and diverse coastal habitats, including eelgrass and salt marsh. In July 2012, we undertook a field validation in this region of the Portable Remote Imaging SpectroMeter (PRISM), a new imaging sensor package optimized for coastal ocean processes. PRISM provides spatial resolutions up to 30 cm and spectral resolutions of 3 nm. In-situ sampling was conducted concurrent to the PRISM flights to measure inherent optical properties of the water column and sample selected benthic and coastal habitat spectral targets. Here, we compare spectra obtained from the orthorectified and calibrated imagery using initial atmospheric correction of the imagery from the ATREM model with those collected from sampling locations within Elkhorn Slough. Excellent agreement between PRISM and in-situ validation spectra provide the foundations for using PRISM to discriminate marine and coastal habitats.