10.0

DLR Processor

8

8

3

3M

• New NetCDF format, replacing the old ENVISAT proprietary format
• New product type (SCI_____1P)
• Improved degradation correction based on a scan mirror model and m-factors.
• Revised algorithms for polarisation, SWIR channels correction, and SMR calculation
• Integration of calibrated lunar measurements into the Level 1b product
• Inclusion of parameters detailing operational status and instrument configuration

Full mission reprocessing 2023

Major algorithm improvements with respect to version 7.04 are the following:

• The stray light correction based on a matrix approach is extended to channels 3-8.
• The memory effect correction (MEC) for limb data is improved, correcting the estimate for the signal of the reset readout at new tangent heights. This is especially significant for measurements above 40 km tangent height.
• The scaling factor used for the non-linearity correction (NLC) for co-added data is corrected. In the previous version NLC was wrongly calculated, when PMD signals were affected by high noise.
• The hot pixel correction for limb dark measurements is completely revised.
• The polarisation correction for occultation is switched off, since no reliable calibration data exist for this case, and no significant amount of polarisation is expected in this mode.
• States used for dark calculation are selected in the configuration file. Only dark states with pixel exposure times between 0.125 and 1 second are used.
• The radiometric calibration uses a new approach: a physical model of the scanner unit including contamination layers (the scan mirror model).
• Radiometric and polarisation key data are updated from on-ground calibrations and adapted for the scan mirror model.
• A correction for the instrument scan-angle dependent degradation is calculated using a scan mirror model.
• Degradation is now corrected in the Level 1 processing (m-factor application) as part of the radiometric calibration.
• Mean PMD values are now corrected for degradation.

Processor version 8.01 was used in the latest SCIAMACHY reprocessing campaign.

• New degradation correction using m-factors.
• Introduction of stray light correction using matrix approach for channel 2
• Mesospheric Limb Measurements performed for 30 orbits every month on two separate days. State ID 55 included in Limb MDS. Measurements not processed to Level 2 products.
• Software patch for scanner encoder values.

• New pointing correction with new SCI_LI1_AX.
• Update of ESA CFI software to version 5.06.
• Correction of a bug (ENVI-NCR-06-1739), impacting Leakage GADS (channels 6-8) for consolidated data processing.

• Polarization correction factors now different from 0
• Corrected order of SMR spectra in Sun Reference ADS
• Corrected sign of solar mean reference spectra in New Sun Reference DS.

• Improved parameterization of the Memory effect for channels 1 to 5
• New correction for Non-Linearity effect in infrared channels
• Improved key data for the radiometric calibration of all channels
• Calibrated and un-calibrated Solar spectra provided
• Orbital dependency of channels 6 to 8 leakage calculated; applied only to channel 8
• Pointing accuracy improved through the usage of the Envisat Restituted Attitude auxiliary files in the off-line processing
• Decontamination flag added to SPH

• Code adaptations to solve performance problems encountered during reprocessing.
• Corrected polarization ratio calculation to remove radiance discrepancies up to 1% between prototype and operational processor.
• Memory leaks eliminated
• Bugs fixed to avoid Level 1b processing crashes

7.1

Offline Processor

3

3M

• New NetCDF format, replacing the old ENVISAT proprietary format
• New product type (SCI_____2P)
• Addition of Tropospheric BrO profile

• Additional Nadir MDS for CH4, HCHO, CHOCHO columns.
• Additional MDS for Tropospheric NO2.
• Noctilucent clouds (NLCs) from limb measurements;
• Improved AAI (now using retrieved ozone values instead of formerly used climatological ones);
• Cloud fraction (cloud/ice separation introduced).
• Ozone profiles retrieval extended up to 65 km.
• The instrument degradation correction (m-factor) is now performed in the Level 0-1b processing

Phase F

DDS generation only

Optimized retrieval settings leading to a significant quality improvement for:

• Nadir SO2 Vertical Column Density (fix for background database; max-SZA cut-off decreased from 89 to 80 deg.; fix quality flag; earthshine stretch implemented; reference Ring spectrum improved; change in eta reference spectrum).

   

• Nadir OClO Slant Column Density (correction of polynomial degree used in DOAS fit; SZA cut-off changed from 95 to 92 deg.).
• Nadir CO Vertical Column Density (introduction of a linear wavelength-dependent wavelength shift spectral correction).

• Starting with processor version 5.01, a new limb retrieval grid of 27 tangent altitudes was adopted instead of the 19 values used previously.
• Additional Nadir MDS for SO2, BrO, H2O, OClO, and CO columns.
• Additional Limb MDS for BrO profiles.
• Limb Cloud MDS contains indicators for cloud presence and type (water clouds, PSCs and NLCs).

• Implementation of SO2 nadir slant columns.
• Implementation of BrO nadir slant columns.
• New Aerosol Absorption Index (AAI) algorithm.
• M-factor application in ozone retrieval.
• Improved calibrations for NO2 nadir retrievals using not radiometrically calibrated Earthshine data and SMR from ASM diffuser (ID 'A0').
• NO2 and O3 limb profile retrievals improved adopting a new forward model (using Picard iteration) and optimised settings.

GOME ATBD4.0

LIMB DDD v2.0

SACURA DDD v1.0

• Updated SACURA cloud algorithm.
• Removed offset applied to NO2 slant column processing.
• Number of retrieved profiles per state set from one to four.
• Cloud and Aerosol MDS filled with next valid value instead of being set to zero
• Molecular Ring correction applied on NADIR O3 slant column density.

Bugs fixed for:

• Interchange of Pressure and Temperature values in LIMB MDS
• Erroneous Cloud and Aerosol Quality Flags
• AAI erroneously set to zero in Cloud and Aerosol MDS
• Error estimate for NO2 profiles higher than expected

• New Nadir UV/Visible algorithm for O3 and NO2 based on the GOME Data Processor Version 4.0.
• Nadir UV/Visible algorithm for cloud-top height and cloud optical thickness based on SACURA.
• Limb UV/Visible products: Stratospheric O3 and NO2 profiles.
• Improved pointing using Envisat Restituted Attitude information in consolidated product