Meteosat-11 and Meteosat-9 SEVIRI decontaminations are planned for early 2020.
Thursday, 12 December 2019
The Meteosat-11 and Meteosat-9 SEVIRI decontaminations will be performed during the one-month Meteosat-10 RSS break, planned from 06/01 to 03/02/2020 and for which there will be no RSS gap filling by Meteosat-9.
The decontamination dates are:
- Meteosat-11: from 13 to 20 January 2020
- Meteosat-9: from 27 January to 3 February 2020
During the Meteosat-11 decontamination period, no Meteosat-11 data will be available. Meteosat-9 Full Earth Scan (FES) data (rectified to 0°) will be disseminated instead, and also one week before and one week after Meteosat-11 decontamination, i.e. from 06/01 to 27/01/2020.
The parallel data from the non-prime FES spacecraft will be distributed on EUMETCast Europe, on EUMETSAT Data Channel 15 (PID: 500, Multicast address: 184.108.40.206). The parallel data will have ‘_PAR’ included in their filenames.
- 06/01: Start of the one-month Met-10 RSS break (06/01 to 03/02).
- 06/01 09:00 UTC to 13/01 09:00 UTC: Met-11 prime FES spacecraft, with both Met-9 and Met-11 image data and Meteorological products disseminated in parallel*. Met-9 data, rectified to 0°, will be distributed on EUMETSAT Data Channel 15, with filenames like:
- 13/01 09:00 UTC to 20/01 09:00 UTC: Met-9 prime FES spacecraft, with image data and Meteorological products (rectified to 0°) disseminated. Met-11 decontamination with no data dissemination. Met-10 available as FES backup in case of Met-9 anomalies.
- 20/01 09:00 UTC to 27/01 09:00 UTC: Met-9 prime FES spacecraft (still), with both Met-9 and Met-11 image data and Meteorological products disseminated in parallel*. Met-9 data rectified to 0°. Met-11 data will be distributed on EUMETSAT Data Channel 15, with filenames like:
- 27/01 09:00 UTC: Met-11 prime FES spacecraft. Met-9 data dissemination stops.
- 27/01 09:00 UTC to 03/02 (time TBC): Met-9 decontamination with no data dissemination. Met-10 available as FES backup in case of Met-11 anomalies.
- 03/02 (time TBC): Met-9 available as backup spacecraft.
- 03/02 08:00 UTC: End of the one-month Met-10 RSS break. Met-10 RSS service resumes.
- 03/02 08:00 UTC: Met-11 prime FES, Met-10 prime RSS, Met-9 FES backup.
* The Geostationary Nowcasting products (Cloud Mask, Cloud Type, Cloud Top Temperature and Height) will not be available from the non-prime spacecraft.
Users wishing to receive the parallel Meteosat data streams should register with our User Service Helpdesk.
For any questions, contact our User Service Helpdesk.
Decontaminating satellite instruments
The instruments on our satellites are routinely checked every year to see if decontamination is needed. The best time to do one is just after the winter solstice. However, as satellites are most heavily contaminated when new, there is often a need to decontaminate more frequently. This is because the contamination is water vapour which is trapped in the coatings used in the satellite manufacture and, so, is launched with the satellite.
The scope of decontamination is to remove ice and other contaminants from the cold parts in the optics. Condensation of particle or chemical contamination on the cold optics of the SEVIRI affects the instrument’s radiometric performance and the bias of the instrument’s final calibrated radiances.
Also, the passive cooling system is impacted by contamination, so that it loses its effectiveness and, in an extreme case, may not be able to maintain the instrument's operating temperature. The contaminants migrate to the cold parts from the rest of the spacecraft over time, caused by things such as condensation of outgassing material from the spacecraft. This rate is higher at beginning of life in orbit as the satellite releases moisture and contaminants when exposed to the deep vacuum of outer space.
For this reason the frequency of decontaminations is higher at beginning of life in orbit and it tends to become very low or null at end of life, as there is no more significant release of moisture and contaminants from the satellite.
The decontamination process
The decontamination operation consists in warming up the optical cold parts up to a temperature that allows both ice and other contaminants to evaporate in space, after which the instrument is allowed to cool down back to 95 K. This is better achieved in the winter season when the solar input helps to warm up the cold parts. During decontamination the instrument is not at its normal operating condition and, therefore, either its performance is degraded or the instrument is non-operational.