The Envisat GDR and SGDR data are generated using two software: the ESA IPF, from Level 0 to Level 1B (that includes the processing of MWR data), and the CNES Bibli ALTI, from Level 1B to Level 2.

The improvements in reprocessing baseline 3.0 relative to the MWR and wet tropospheric corrections are listed below, further details can be found in the product handbook: 

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

MWR Level 2 processor

• NetCDF format (standard and enhanced datasets)
• New dry and wet tropospheric model corrections computed from the integration of ECMWF ERA-Interim profiles at the altitude of the measurement
• 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
• Updated rain flag and sea ice flag tuning
• New maneuver flag field
• New surface classification and distance to shore fields
• New continental ice flag field