Space-borne synthetic aperture radar of intertidal flat surfaces as a basis for predicting benthic macrofauna distribution
Daphne van der Wal, Peter M.J. Herman and Tom Ysebaert
Abstract
High resolution, synoptic information on sediment characteristics of tidal flats is
required for habitat mapping, and for assessing the distribution of benthic
macrofauna. This study aims to derive information on surface characteristics of
tidal flats from space-borne Synthetic Aperture Radar (SAR). Estimates of the
backscatter coefficient were extracted from ERS-1 SAR and ERS-2 SAR PRI imagery
of two tidal flats in the Westerschelde. They were related to field
measurements of surface roughness, moisture conditions, sediment
characteristics (median grain-size and silt content) and densities of benthic
macrofauna. As predicted by the IEM backscattering model, a significant
positive relationship was found between surface roughness and the backscatter
coefficient: rougher surfaces were associated with higher backscatter values. In addition, median grain-size was
positively correlated with backscatter, and silt content was negatively
correlated with backscatter. Surface roughness was related to sediment
characteristics: sandy sediment was found to be rougher than finer sediment,
because surface ripples were more pronounced in the former. Significant
relationships were also found between the sediment characteristics and
macrofauna density. Relationships between sediment characteristics and
backscatter were generally consistent in time. This demonstrates the potential
of SAR for habitat mapping.
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History
Submitted: 07 June 2003
Revised: 02 February 2004
Accepted: 10 February 2004
Citation
van der Wal D, P M J Herman & T Ysebaert, 2004. Space-borne synthetic aperture radar of intertidal flat surfaces as a basis for predicting benthic macrofauna distribution. EARSeL eProceedings 3(1), 69-80
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ISSN 1729-3782
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