Tuesday, May 10, 2016

We are pleased to announce that reprocessing of all Jason-1 data, as version “E”, is now complete and available for download.

This release includes reprocessed data from primary, tandem, and geodetic mission phases, which spans 2002-2013 and includes repeat cycles 1-373, 500-537.
This new release takes into account user and cal/val feedback from last year’s beta release.
Products from this updated release have creation dates (“history” parameter on products) of January 2016 and later.
Products from the last year’s beta release have creation dates in 2015, and should be discarded.
The reprocessed data are now available as version "E" GDR data products at PO.DAAC: podaac-tools.jpl.nasa.gov/drive/files/allData/jason1/L2
All products are available in NetCDF format, and are available in three forms, similar to those from the Jason-2/OSTM mission:

  1. The native (N) dataset containing 1-Hz records as well as 20-Hz high-rate values (GDR)
  2. The reduced (R) 1-Hz subset of the full GDR data set. (GDR-SSHA)
  3. The expert sensor (S) data set containing the full radar-echo waveforms (S-GDR) in addition to the GDR dataset.  

All other data (N) and (R) from ALL cycles)  are now available at PO.DAAC.
A User Handbook is provided at: podaac-tools.jpl.nasa.gov/drive/files/allData/jason1/L2/docs/Handbook_Jason-1_v5.1_April2016.pdf
The User Handbook provides details on the evolution of the version "E" products compared to the preceding version "C" products.

The primary evolutions include:

  1. Products are provided in NetCDF format instead of binary.
  2. Orbit solutions are from so-called version "E" standards, based on ITRF08.
  3. Time tags are adjusted to correct for the datation bias that existed in previous versions (A, B, C) of the Jason-1 products.
  4. Altimeter range instrument correction and associated Ku- and C-band range account for error in internal path delay.
  5. Recalibrated radiometer data generated in 2015, and application of near-land path delay algorithm.
  6. Altimeter wind speeds are recomputed using recalibrated atmospheric attenuations from radiometer.
  7. New Ku- and C-band sea state bias models generated in 2015, and values that are computed using revised wind speeds.
  8. The ionosphere correction is recomputed using updated altimeter ranges and sea state bias correction
  9. Current state-of-the art geophysical models including:
    • Model dry troposphere correction from ECMWF Reanalysis (ERA) in addition to previously available operational ECMWF
    • Model wet troposphere corrections from ECMWF Renalysis (ERA) in addition to previously available operational ECMWF
    • Model wind speeds from ECMWF Reanalysis (ERA) in addition to previously available operational ECMWF.
    • Inverse barometer and high-frequency corrections using ECMWF Reanalysis (ERA) in addition to previousl available operational ECMWF.
    • Ocean tides from FES2014 and GOT4.10 models
    • Mean sea surface from MSS_CNES-CLS11, computed from a 20-year reference period.
    • Mean dynamic topography from MDT_CNES-CLS13
    • Geoid from EIGEN2008
    • Bathymetry from DTM2000.1
    • Rain flag updated