Minimize Processor Release

The Envisat GDR and SGDR data are generated using two software: the ESA IPF, from Level0 to Level1B, and the CNES Bibli ALTI, from Level1B to Level2. Moreover a dedicated RAIES (Radar Altimeter Individual EchoeS) L1B processor have been developed for processing the individual echoes. The results are appended to the SGDR products, including the power and phase individual waveforms, power scaling factor, tracker range, geolocation, altitude, time tagging.


  Envisat V2.1(+) Envisat V3
Range Historical L1b (+PTR drift correction Including PTR and L1b updates
Orbit GDR-C (GDR-D) GDR-E (GDR-D if DORIS is missing)
Sea State Bias SSB V2.1 SSB V3
Ionosphere Lanczos filtering for cycle<64, GIM after Iterative filtering for cycle<64, GIM after
Wet troposphere MWR V2.1 (V2.1+) MWR 5 params solution
Dry Troposphere ECMWF Gaussian grid based
Combined Atmospheric Correction MOG2D High Resolution
Ocean Tide FES GOT 4V8 FES 2014B
Solid Earth Tide Elastic response to tidal potential
Pole Tide WAHR85

Table of main changes from processing baseline 2.1 to 3.0

A more detailed list of the improvements in reprocessing baseline 3.0 are shortly reported below, further details can be found in the product handbook:

RA2 Level 1 processor
New independent CAL1 (PTR) Time delay & Power corrections calibration processing chain. After EOM scenario approach
New independent IF-mask processing chain. After EOM scenario approach
New independent ICU (Envisat platform clock) & USO (RA2 range clock) smoothing strategy. After EOM scenario approach
Updated main L1B Measurement Chain, in agreement with the new calibration approach
Generated Calibration files for each of the Calibration Chains (PTR, USO, IF-mask) for the whole mission
New generated Auxiliary Characterisation files
Update of the RAIEs Individual Processor to the last L1B processing version
Generated RAIES NetCDF files to be appended to the L2 enhanced products
MWR Level 1b processor
Updated in-flight calibration insuring consistency between the L2 retrieval algorithms and the RA2-MWR observations
Updated side lobe correction tables accounting for the actual antenna patterns


Level 2 processor
NetCDF format (standard and enhanced datasets)
Updated Orbit standard: GDR-E
Updated MSS model: CNES CLS 2015
New MSS field, added as a second solution: DTU 15
Updated solution 1 tide model : GOT 4.10c
Updated solution 2 tide model: FES2014b
New long period non equilibrium field: FES2014b
Updated ODLE model: ACE-2
Updated Geoid model: EGM2008
New MDT field: CNES-CLS2013
New dry and wet tropospheric model corrections computed from the integration of ECMWF ERA-Interim profiles at the altitude of the measurement
New barometer height and u/v-component of the wind speed computed from ECMWF ERA-Interim maps
New field for MOG2D High Resolution. Ocean model forced by ECMWF ERA-Interim atmospheric pressures
Updated radiometer wet tropospheric correction: improvement of the retrieval estimation
New radiometer wet tropospheric correction field computed using lapse rate and sea surface temperature as additional input together with the brightness temperatures and the backscatter coefficient
New GPD+ wet tropospheric correction field
Updated backscatter coefficient atmospheric attenuation and alternative computation from model wet tropospheric correction
New SWH modeled instrumental corrections
Updated Sea State Bias derived from 1 year of ENVISAT altimeter data with version " Baseline v3.0" geophysical models
Updated backscatter to altimeter wind-speed adjustment to account for ENVISAT reprocessing Baseline V3.0 standard
Updated rain flag and sea ice flag tuning
New sea surface height anomaly fields
New filtered ionospheric correction field issued from CNES SLOOP project (median and Lanczos filtering)
New maneuver flag field
New surface classification and distance to shore fields
New continental ice flag field
New echo and geo corrections fields (LEGOS Ice-2 corrections)
New 2-kHz individual echoes fields (enhanced products only)