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Start of Envisat RA-2 Mission reprocessing campaign at F-PAC

17 March 2011

The full-mission reprocessing of the Envisat Altimetry Level 2 data set V2.1 has commenced at F-PAC.

The reprocessing activity covers the Envisat Altimetry data set for the time range from 10 April 2002 (orbit 580 - cycle 5) to 19 September 2010 (orbit 44643 cycle 92).

The reprocessing campaign is performed with the IPF version 6.04 (L1b) and CMA processor version 9.3 (L2) and the CNES GDRC precise orbit products.

Please, refer to the ESA news and reports here below for further details on the Altimetry processors and validation results:

ESA news:

The reprocessed Envisat Precise Orbit Products are available online from diss-nas-fp.eo.esa.int server (under directory /doris/vor_version_2009).

ESA related documents & reports:

Reprocessing schedule:

The schedule of the reprocessed cycles will be as follow:

  • Starting from cycle 10 up to cycle 92;
  • From cycle 5 to cycle 9.

Where to find ENVISAT Altimetry Data Set 2.1:

The ENVISAT Altimetry Data Set 2.1 with processing stage flag "R" are made available progressively at F-PAC from diss-nas-fp.eo.esa.int server.

The reprocessing campaign generates systematically following L2 products:

  • RA2_GDR_2P (under directory /altimetry_dataset_v2.1/gdr)
  • RA2_MWS_2P (under directory /altimetry_dataset_v2.1/sgdr)

To be noted that with this new release all products of one day are zipped in one single ZIP file.

A generic note was written to estimate the Envisat V2.1 reprocessing impact on the main altimetric parameters:

  • Major evolutions compared to the previous current version
  • Total bias evaluated on the SLA monitoring
  • Geographic and temporal differences of New and Old versions

The technical note can be found under: /altimetry_dataset_v2.1 directory/gdr_validation_report/V2.1_reprocessing
_impact_on_altimetric_parameters.pdf

All Level 2 products with processing stage flag "O" corresponding to the CMA predecessor processor version 9.02 will remain on the F-PAC FTP server (diss-nas-fp.eo.esa.int) for a limited period of time (3 months) after release of reprocessed version. Old Precise Orbit Products will also remain. The products are located under:

  • RA2_GDR_2P (under directory /gdr or altimetry_dataset_2.0/gdr)
  • RA2_MWS_2P (under directory /sgdr or altimetry_dataset_2.0/sgdr)
  • DOR_VOR (under directory doris/vor )

USO Correction

The user should be aware that the new processor baseline and the products will include the Ultra Stable Oscillator (USO) clock period correction. For this reason, the external USO clock period correction should not be applied anymore to the RA-2 products (as it was for previous version) and the generation of the external USO clock period correction files has been stopped.

Please note that routine production is still available under:

  • RA2_IGD_2P (under directory /igdr)
  • RA2_WWV_2P (under /imar)

Please contact EO Help if further clarification is required.