Geotechnical Site Characterization of Sandy Beach Sediments from Satellite-Based Synthetic Aperture Radar Imagery: Fid-Bau Portal

Geotechnical Site Characterization of Sandy Beach Sediments from Satellite-Based Synthetic Aperture Radar Imagery

Paprocki, Julie / Stark, Nina / Graber, Hans C.

The potential use of synthetic aperture radar (SAR) imagery for estimating moisture contents at sandy beaches is discussed. These systems are considered all-weather satellites, can provide data during storm events, and allow for the monitoring of sandy beaches during adverse conditions. SAR images are composed of the backscatter coefficient, which is a representation of the returned energy. It is impacted by radar properties (wavelength of the transmitted signal, incidence angle, and polarization) and terrain characteristics (dielectric properties, surface roughness, and feature orientation). Typical trends in backscatter, moisture content, surface roughness, and roughness category are presented for a case study from the sandy Atlantic beach in Duck, North Carolina, and potential models how to address these factors in a data analysis framework are discussed. Moisture contents here ranged from 3.7% to 23%, backscatter coefficient ranged from –20.5 dB to –13.3 dB, and standard deviation of the surface height variation (or RMS height) ranged from 0.101 to 0.491 cm. Preliminary results indicate that SAR images are a feasible option for the derivation of moisture content data, especially for images collected at intermediary incidence angles (~30°–46°).