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Reprocessed ESA ERS Altimetry (REAPER) dataset soon available

13 May 2014

The full-mission reprocessing of the ESA ERS Radar Altimetry (RA) Level 2 data has now started.

The REAPER (REprocessing of Altimeter Products for ERS) project covers both the ERS-1 and the ERS-2 Altimetry missions. The reprocessed data set spans from the start of the ERS-1 mission in July 1991 to June 2003, when the loss of the ERS-2 on-board data storage capability occurred causing the end of the ERS-2 global mission coverage. Availability of the commissioning phase data for ERS-1 (July-December 1991) and ERS-2 (April-August 1995) might be decided at a later stage based on the outcome of the data validation.

The REAPER Product Handbook provides exhaustive information on the new ERS RA products format and improvements. The REAPER products will be delivered in netCDF format (version 3.6). Some products for ERS-1 and ERS-2 are available as samples.

The reprocessing campaign will be performed with REAPER processor version 1.08 and use of the latest reprocessed ESA precise orbit products (see ESA news "Homogeneous reprocessed ERS-1 and ERS-2 Orbit data set")

Data Access

The REAPER Altimeter ERS dataset is expected to be made available to users by June-July 2014. The data will be freely accessible via Fast Registration.

Data Processing and Quality Improvement

Major improvements with respect to the previous ESA RA products format (OPR - Ocean Product - and WAP - Waveform product) have been implemented (e.g. the 4 Envisat RA-2 retrackers, RA calibration improvement, new reprocessed Precise Orbit Solution, ECMWF ERA-interim model, NICO09 ionospheric correction until 1998, GIM ionospheric correction up to 2003, new SSB, etc.)

The assessment of the REAPER data quality versus the ERS OPR and WAP data shows a clear improvement in terms of accuracy over the tandem periods between ERS-1, ERS-2 and Envisat missions (currently assessed periods).

Future Reprocessing

ESA is planning to further improve the ERS dataset by extending the time coverage up to 2011 and also continuing to increase the data quality. For this reason a future reprocessing is foreseen by the end of 2015.

Any feedback or recommendation for additional improvement from the user community is welcome through EOHelp.