Sciamachy Detector Monitoring Facility (SDMF)
Monitoring of the Sciamachy Instrument, and in particular the detectors is performed using the Sciamachy Detector Monitoring Facility (SDMF), constructed by and operated at SRON. Monitoring is based on available Lv. 0 data. Regularly updated results of key (detector) monitoring parameters can be found in the Monitoring menu at the left hand side of this page.
Purpose of the SDMF is to generate auxiliary data that can be used to improve the calibration with respect to the currently available operational Lv. 1b products. SRON, therefore, patches the operational Lv. 1b products by replacing calibration parameters in the operational Lv. 1b files, thus establishing a dynamic test-environment for calibration improvements.
Implemented options in version 4.0 of the patching S/W are:
- Update Main Product Header to identify patched product and version
- Memory-effect correction and non-linearity correction:
- including PMD scaling, for co-added read-outs
- no correction of the first read-out after reset
- Dark signal, using daily darks (Channel 6-8)
- Orbital variation of dark signal (Channel 8, including transmission correction)
- Polarisation improvements as in “Verification 2005”
- Dynamical BDPM ( “smoothed” mask, 50-orbit window)
- (not applied) PPG correction
- (not applied) Radiometric keydata update (IFE)
The output of the patch-S/W is again a valid Lv. 1b product. The patched Lv. 1b are, free of charge and made available via the Dutch Sciamachy data center. Registration for access to the patched Lv. 1b products can be arranged by clicking here (via http://www.sciamachy.org/products and click
spectra, level 1b data ->
SRON). Patched Lv. 1b data after registration is available via
As mentioned above, monitoring is based on available Lv. 0 data. The monitoring parameters are calculated for each new Lv. 0 data file added to the database. For both near-real time and consolidated files the following processing steps are performed:
- Extraction of the required calibration states [StateId’s: 65, 46, 63, 67, 26, 8,16, 48, 39, 61, 62, 52, 59, 69, 70, 1, for reference see the state description at the SOST web page], averaging of data within one state-execution, calculation of histograms, and storage to HDF5 monitoring database.
- Extraction of sun and last limb spectra to (highly) complete HDF5 databases.
- Calculation of the Dark Signal (analog offset and dark current)
- State dark for channels 1-6
- State dark for channels 6+ and 8, including Random Telegraph Signal statistics
- Fitted dark for channels 1-7
- Fitted dark for channel 8 (with Orbital Variation, from monthly calibration orbits)
- Calculation of Solar Mean Reference spectrum
- Calculation of the Transmission to monitor:
- the instrument degradation (channels 1-6)
- Ice Effects (channels 7 and 8)
- Calculation of the Pixel Gain from WLS measurements
- Calculation of the Bad and Dead Pixel mask for:
- 1 orbit (orbital pixel mask)
- Last 50 orbits (smooth pixel mask, used for Lv. 2 retrievals)
- Store key monitoring parameters per channel (apart form the parameters described above, also the OBM and detector temperature) and per pixel for viewing.
The monitoring database is updated daily by processing the newly arrived Lv. 0 files. The output of the SDMF is direct input to the Lv. 1b patch-product.