Interpretation of SAR Imagery of Vestfjorden, Norway

      E G Mitchelson-Jacob, B Jones and J C Scott

  The oceanography of Vestfjorden, which lies between the Lofoten
  archipelago and mainland Norway, is dominated by two major currents;
  the Norwegian Coastal Current flowing north along the mainland coast
  and the Norwegian Atlantic Current following the shelf break further
  offshore.  Studies of AVHRR SST imagery show that both currents are
  bathymetrically-steered by the banks and troughs in this region.
  Although there is some freshwater and tidal influence in Vestfjorden
  the surface circulation patterns induced by the currents are
  wind-dominated.

  ERS-1 SAR data for Vestfjorden clearly show water of differing surface
  roughness.  The interpretation of the imagery is dependent on the
  ability to distinguish the origin of these features, whether
  oceanographic or meteorological.  There is particular difficulty in
  the interpretation of areas of reduced surface roughness in regions of
  complex coastlines.  Low backscatter can result from wind shadowing or
  the prescence of natural slicks which frequently occur in relation
  to this area's many fjords and islands.

  A simple wind model has been developed for Vestfjorden to examine the
  effects of topography on the local wind field and the resulting
  meteorologically-induced surface roughness patterns,  A comparison of
  the results  of the model and the actual SAR imagery allows a first
  order separation of the oceanographic and meteorological effects.

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