On the use synergy of ERS scatterometer, altimeter and SAR for wind
  retrievals.

  by

  J.A.Johannessen, Earth Sciences Division, ESA-ESTEC, 2200 AG Noordwijk,
  The Netherlands (jjohanne@jw.estec.esa.nl), Julia Figa, KNMI, De Bilt,
  The Netherlands, and Erik Korsbakken, Nansen Environmental and Remote
  Sensing Center, Bergen, Norway.


  During the ERS-1/2 tandem mission overlapping coverage at high to
  moderate latitudes from the combination of the different microwave
  sensor on the two satellites were achieved within a time separation of
  only 30 minutes.  This situation opens up a wide range of opportunities
  for utilization of instrument synergy in Earth Observation.

  In this presentation the synergy between the wind scatterometer (Scatt),
  the radar altimeter (RA) and the synthetic aperture radar (SAR) will be
  examined for the Greenland Sea . In doing so we will assume that the
  near surface wind conditions remain unchanged over the 30 minutes
  interval. First, we conduct a validation-by-comparison of the
  relationship of the radar backscatter observed by the three sensors
  (Bragg or specular) to the retrieved near surface wind speed.  The near
  coincident reported large scale meteorological condition is used as
  control data. Second, the impact on the wind retrievals by the
  different sensors as influenced by the spatial resolution, the
  directional properties of the wind and the waves as well as the wave
  height will be examined. This will be done both within zones of uniform
  radar backscatter and in vicinity of wind fronts and coastal boundaries.
  The main results will be discussed and interpreted in light of the
  strengths and limitations of the different sensors.

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