A Reanalysis of ERS-1 Radar Altimeter Data for Ocean Circulation Studies.

C. J. Koblinsky [Oceans and Ice Branch, NASA Goddard Space Flight Center,
Greenbelt, Maryland 20771, USA, (koblinsky@gsfc.nasa.gov)] and B.D. Beckley
[Hughes STX Corp., Greenbelt Road, Greenbelt, Maryland, 20770, USA,
(brianb@odyssey.stx.com), (http://neptune.gsfc.nasa.gov/ocean.html).

The goal of the NASA sponsored Ocean Altimeter Pathfinder Project is to
reprocess all satellite altimeter data sets with improved algorithms to
provide a consistent and validated global view of sea surface topography
over the past two decades. The first stage of this project has been
completed for Geosat, ERS-1, and TOPEX/POSEIDON.  In this presentation, we
will highlight work with the ERS-1 data set and demonstrate its value to
the new climatology.  In particular, we are blending ERS-1 and
TOPEX/POSEIDON data sets to provide a high resolution view of sea surface
topography variations between 1992 and the present.  As part of the
pathfinder goals, we have improved the precision of the ERS-1 altimetry.
The cross over variation of these reprocessed ERS-1 altimeter data is 5.6
cm rms over the Phase C part of the mission.  This can be compared with 3.3
cm rms that is found for TOPEX/POSEIDON over three years.  The combined
TOPEX/POSEIDON and ERS-1 data set has a residual of 4.9 cm rms.
Comparisons between these data sets with tide gauges and general
circulation models will be shown at the meeting.

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