SCIAMACHY PMD Long Term Monitoring Results
The plots displayed on this page show results of the monitoring
of SCIAMACHY's Polarisation Measurement Devices (PMDs).
Note that the monitoring data presented here have been reprocessed using
actual (Level 1b V6.x upwards) radiometric key data.
Results are presented for the different SCIAMACHY light paths/viewing
geometry (sun via the ESM mirror through the subsolar port and WLS via
- Limb/occultation geometry (sun via ASM and ESM mirrors)
- Calibration light path (sun via ASM mirror and ESM diffuser)
Note that the subsolar data have been derived from pointing
are performed less frequently than the fast sweep measurements which
used for the science channels results
All measured signals (in low gain) have been divided by the
corresponding measurement at a reference time (currently 2 August 2002,
at about orbit 2200), yielding an effective throughput for the
different PMD light paths.
Measurements performed during times of reduced instrument performance
(e.g. switch-offs or decontamination periods) have been omitted.
Since the PMDs are broadband devices, no spectral averaging is required.
The plots are updated on a daily basis, thus reflecting the current
status of the instrument.
PMD 1 (Click to Enlarge)
PMD 2 (Click to Enlarge)
PMD 3 (Click to Enlarge)
PMD 4 (Click to Enlarge)
PMD 5 (Click to Enlarge)
PMD 6 (Click to Enlarge)
PMD 7 (Click to Enlarge)
- General remark:
The results presented here are based on the analysis of uncalibrated
(Level 0) data, which have been corrected for dark current (constant
(approximate) PMD scan angle dependency, and the
seasonally varying distance to the Sun. Therefore variations smaller
than about 1% require careful
- The timing of subsolar measurements before 30 November 2002
(about orbit 3922) did not consider the known yaw misalignment of
on ENVISAT. The timing has been corrected in the final flight settings.
Therefore, subsolar measurements from 2002 are not plotted, and all
subsolar measurements have been referred to orbit 4519 (10 January
2003, just after a long decontamination phase).
- PMD 7 results are probably dominated by straylight and not
reliable. They are only shown for completeness.
- WLS data are only available for PMD 1 to 3 because of saturation
in the other PMD channels.
- PMD 4 seems to degrade much faster than the other PMDs (except
for PMD 7, which covers the same spectral range). This issue is under
- The PMD 6 dark signal shows a strange variation which is
currently under investigation.
- There are still some seasonal effects visible in the data which
need to be corrected (especially for larger wavelengths).
Stefan Noël (firstname.lastname@example.org)