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EARSeL: 2nd Workshop on Remote Sensing of the Coastal Zone Porto, Portugal, 9-11 June 2005 |
SESSION PA2 COASTAL ZONE MANAGEMENT (cont.) |
Gerold Brink-Spalink, Emil Stanev, Jörg-Olaf Wolff
ICBM, Carl von Universität Oldenburg, 26111 Oldenburg
g.brink-spalink@icbm.de, e.stanev@icbm.de, wolff@icbm.de
Nina Gemein, Rainer Reuter
Institut für Physik, Carl von Universität Oldenburg, 26111 Oldenburg
nina.gemein@uni-oldenburg.de,, rainer.reuter@uni-oldenburg.de,
The MERIS ocean colour instrument onboard ENVISAT provides a 300 m geometric ground resolution which allows to derive images of small coastal zone features such as the EAST Frisian islands and the surrounding tidal flat areas. MERIS images are thus suitable to display patterns of suspended matter distributions as they typically occur due to tides, currents, meteorological forcing and the bathymetry in these regions.
For an understanding of the complex sediment dynamics in these tidal flats a hydrodynamic model has been developed which is coupled with a sediment transport model with a horizontal resolution of 200 m. Besides larger particles with a medium size of 200 µm which are dominating close to the sea bed and are responsible for changes of the bottom topography, dynamics of smaller mud particles in the 10 µm range is simulated which are typically present in the entire water column and are thus visible in satellite images.
The simulated concentration of near-surface suspended particles displays a rigorous dynamics which is forced by transport and turbulence. Tidal channels act as pathways transporting sediment between tidal flats and open sea where a pronounced temporal asymmetry is observed shaped by the asymmetric ebb-dominated tide. To verify the numerical model, its results are compared with sediment patterns observed in MERIS images. The consequences for the net transport of suspended particles between open sea and back-barrier tidal flats is discussed.
Last Update: 2005-03-16