Hyperspectral Optical Characterization of Bottom/Resuspended Sediment in the Surf Zone


Charles Walker

Funding Source

Naval Research Laboratory


Establish passive remote sensing optical spectral reflectivity and its spatial/temporal variability in the surf zone due to resuspended particles. Relate the observed reflectivities to the particle size distributions, bottom material/reflectivities, and in situ in-water optical properties. Relate the temporal and spatial variability of these optical properties to the hydrodynamical forcing and evaluate the applicability of coastal optics remote sensing models within the surf zone. Inversion techniques will be developed to allow the extraction of bottom, resuspended sediment, and hydrodynamic properties from hyperspectral remote sensor imagery. The imagery will be used to evaluate the validity of point measurements in representing a larger two dimensional area.


A number of hyperspectral sensor flights utilizing the Compact Airborne Spectrometer Instrument (CASI) will be conducted during the August period. The CASI sensor permits the collection of spectral data at a resolution of 1.8 nano-meters from 418 to 927 nano-meters simultaneously along up to 39 ground profiles (look directions). Along-track spatial resolution is dependant on the integration time of the detectors and the flight speed. In addition to the spectral mode, the CASI can collect imagery in a spatial mode in up to 15 separate spectral bands with a 1.2 milli-radian cross-track resolution. Supporting in situ optical measurements will be obtained from a "deep water" (8 meter depth) moored optical sensor and sled mounted sensors. Additional spot water reflectance spectra will be obtained from along the pier and for selected areas on the beach for calibration.

Collaboration: Thornton

For a list of addresses of the investigators involved in Duck 94 click here.