Sedimentation balance in Hai Phong Bay (Vietnam) using remote sensing data.
Ozer André* and Jaspar Annick* in collaboration with HAECON N.V.**
*Laboratoire de Géomorphologie et Télédétection, Université de Liège, Avenue du 6 Août, 2, B-4000 LIEGE.
Phone: +32 4 366 53 35
Fax: +32 4 366 57 22
** HAECON N.V., Harbour & Engineering Consultants, Deinsesteenweg, 110, B-9031 DRONGEN.
Phone: +32 9 226 50 94
Fax: +32 9 227 61 05
The objective of this research is the study the sediment transport in the access channel of the Hai Phong harbour by means of SAR and optical images (SPOT and LANDSAT TM).
During the wet period, fluvial sediment inflow is very significant. In the western bay, optical images show sedimentary plumes stretching for a distance of 20 km. Water colour is correlated with sediments concentration. The distribution of spectral values reveals the variations of concentration.
From these observations it is possible to determine that the direction of very strong currents is oriented towards north. They deflect the progression of sediments coming from the Nam Trieu Channel towards east along the coast of the Ha Nam Island till a shoal where they are deposited. In a different situation, currents are oriented to the south. The flows are not stopped. The highest concentration is located in the Nam Trieu Channel and progressively decreases towards the south.
During the dry period, no sediment inflow is visible. Excepted in the Nam Trieu Channel where sea bottom characteristics are variable, the superposition of the bathymetry (HAECON, 1993) and images shows a good correlation between depth and spectral values.
A multitemporal processing has been carried out to enhance the sedimentary plumes in the Nam Trieu and localise highest sediment concentrations' area.
On one SAR image four phenomena appear: low sea surface roughness of wind protected area; linear high sea surface roughness area, linear oil slicks; a boundary between two water masses.
We are now analysing two recently received SAR images.
SAR, SPOT, LANDSAT, sediment balance, Hai Phong.
Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry
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