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Characterisation of surface roughness and sediment texture of intertidal flats using ERS SAR imagery

Van der Wal, D. and Herman, P.M.J. and Wielemaker-Van den Dool, A. (2005) Characterisation of surface roughness and sediment texture of intertidal flats using ERS SAR imagery. Remote Sensing of Environment, 98, 96-109. ISSN 0034-4257.

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Official URL: http://dx.doi.org/10.1016/j.rse.2005.06.004

Abstract

High resolution, synoptic information on sediment characteristics of intertidal flats is required for coastal management, e.g., for habitat mapping and dredging studies. This study aims to derive such information from space-borne Synthetic Aperture Radar (SAR). Estimates of the backscattering coefficient were extracted from ERS-1 SAR and ERS-2 SAR PRI imagery of four intertidal flats in the Westerschelde (southwest Netherlands). They were related to field measurements of surface roughness, moisture conditions and sediment texture. The field data were also used as input to the backscattering model IEM. The data and model predictions show that on the intertidal flats, backscattering depends mainly on vertical surface roughness, with rougher surfaces associated with more backscattering. Surface roughness, mainly determined by the ripple structure of the bed, decreased with the amount of mud in the sediment. This resulted in a significant negative correlation between backscattering and mud content, and a significant positive correlation between backscattering and median grain-size of the sediment. Sediment texture was also correlated with the volumetric moisture content of the sediment, with finer sediments being associated with higher moisture contents. However, moisture contents were generally high, and therefore the backscatter signal was not sensitive to differences in moisture content. The relationships allowed the development of regression models for the prediction of surface characteristics from SAR imagery, from which maps of, for example, mud content, have been derived. [KEYWORDS: SAR ; Surface roughness ; Mud content ; Sediment grain-size ; Mapping ; Ripple marks]

Item Type:Article
Institutes:Nederlands Instituut voor Ecologie (NIOO)
ID Code:11808
Deposited On:23 Nov 2011 01:00
Last Modified:24 Apr 2012 16:32

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