Arabian Sea Surface Winds and Ocean Transports Determined From ERS-1
  Scatterometer

  David Halpern
  Jet Propulsion Laboratory
  Pasadena, CA 91109, USA

  Satellite scatterometer wind velocity measurements are a new source of
  data for studies of seasonal-to-interannual ocean-atmosphere interactions
  in the Arabian Sea, where the largest and steadiest wind speeds occur in
  northern summer.  Three satellite wind velocity data products (named
  CMOD4, FD and IFR2), all created from radar backscatter measured by the
  first European Remote Sensing Satellite (ERS-1), were compared to
  moored-buoy wind measurements recorded in the central Arabian Sea during
  October 1994 to October 1995.  Orthogonal regression analysis of 75
  collocations indicated IFR2 winds data were more representative of buoy
  winds compared to CMOD4 and FD.  Arabian Sea wind-driven current
  transports computed with July 1995 IFR2 and European Centre for
  Medium-Range Weather Forecasts (ECMWF) data differed by 100%.  That ECMWF
  results were larger were a priori expected.  At 8.5N along the southern
  boundary of the Arabian Sea, the IFR2 meridional Ekman transports agreed
  with at-sea current observations recorded in June and September 1995.  At
  8.5N, IFR2 Sverdrup transports agreed with Somali Current transports
  determined from at-sea current observations in June and September 1995.
  The seasonal cycle of IFR2 winds, including time of monsoon-wind onset
  along the Somali Jet, is described.  IFR2 monthly mean wind-driven ocean
  transports were computed from 1992 to 1996.  During the June - September
  southwest monsoon, 3.4 Sv (1 Sv = 10**6 m**3 s**-1) were upwelled into
  the Ekman layer of the Arabian Sea north of 8N, which was one-third
  smaller than that exiting within the Ekman layer across the southern
  boundary of the Arabian Sea.  The June - September Somali Current
  transport index at 8.5N was 15 Sv.  Year-to-year variations were
  negligible.

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