1. GOME-2 level 1: calibrated radiances from two Metops – slit function performance, signal forecasts and EoL activities
Rűdiger Lang, Rose Munro, Antoine Lacan, Christian Retscher, Gabriele Poli, Michael Grzegorski, Alexander Kokhanovski, Ed Trollope and Richard Dyer
EUMETSAT

2. Outline Slit-function performance and change
Update on instrument degradation
Degradation Forecast
End of orbit maintenance: loss of solar visibility scenarios
Metop-A End-of-Life

3. The GOME-2 instrument on Metop Measuring atmospheric composition
Wavelength [nm]
GOME-2 main channel transmittance
Aerosol O3
HCHO
SO2
BrO
OClO
NO2
(O2)2
H2O O2
I/I0
GOME-2:
series of 3 instruments on Metop (Metop A launched in 10/2006)
sun-synchronous orbit, 09:30
412 orbits (29 days) repeat cycle
Global coverage 1.5 days
240 nm to 800 nm
0.25 to 0. 5 nm spectral resolution (FWHM)
4 channels with 4098 energy measurements of polarisation corrected radiances (40 x 80 km2)
2 channels with 512 energy measurements of linear polarised light in perpendicular direction (S/P) (40 x 10 km2)
Orbit file sizes
GOME-2 L1B ~ 1GB
IASI L1C ~ 2GB

4. GOME-2 optical layout
Scanning grating spectrometer with a random-access linear silicon photodiode array

5. Timelines for the Metop / GOME-2 level 1 products
Processor versions: Reprocessed and NRT data
Release of second set of reprocessed level 1 data (R2) from Metop-A GOME-2 in August 2012
(Covering: 25th January 2007 to 25th January 2012)
Metop-B with GOME-2 flight-model 2 (FM2) launched in-orbit 17th September 2012
Metop-A GOME-2 will continue until launch of Metop-C (October 2017)
Oct 2018
Today
Sep 2012
Jan 2012
Jan 2007
Metop-A / GOME-2 level 1 processor version 5.3.0
Metop-B / GOME-2 version 5.3.0
Future NRT versions
TBD
Metop-C / GOME-2 Future NRT version R2
Metop-A
Metop-B
Metop-C

6. Slit function characterization – FM3/Metop-A FWHM FM3 from on-board spectral light source – Stability in time
GOME-2 FM3 Metop-A
Is this and an effect of thermal environment changes, or due to throughput degradation?
Hypothesis: slowly decreasing FWHM due to thermal changes and throughput degradation.

7. Slit function characterization – FM3/Metop-A Degradation study IUP Bremen (Dikty/Richter)
GOME-2 FM3 Metop-A
In calibration of GOME-2 solar spectra on Kurucz Fraunhofer atlas the FWHM (of a Gaussian slit function) is also fitted
FWHM changes consistently over channel 2
FWHM decreases over time
No effect of throughput test

8. Slit function characterization – FM2/Metop-B Comparison Slit-function FWHM on-ground/in-orbit (29th October 2012)
GOME-2 FM2 Metop-B

9. Slit function characterization – FM2/Metop-B FWHM FM2 from on-board spectral light source – Stability in time
GOME-2 FM2 Metop-B

10. Slit function characterization – FM2/FM3 FWHM FM2/FM3 from on-board spectral light source – Stability in time
GOME-2 FM3 Metop-A
GOME-2 FM2 Metop-B
Metop-B / FM2
Metop-A / FM3

11. Slit function characterization – FM2/FM3 FWHM FM2/FM3 from on-board spectral light source – Long-term stability in time
GOME-2 FM3 Metop-A
GOME-2 FM2 Metop-B
Metop-A / FM3
Metop-B / FM2
OB temperature (ONA0281) GOME-2 /Metop-B
OB temperature GOME-2 /Metop-A

12. Courtesy, A. Richter, IUP, Univ. Bremen
Slit function characterization – FM2 FWHM FM2 from on-board spectral light source – orbital variation
GOME-2 FM2 Metop-B
Change of FWHM along the orbit at 455 nm for Metop-B / FM2.
Courtesy, A. Richter, IUP, Univ. Bremen
Optical bench temperature change along one orbit for Metop-B / FM2.

13. Slit function characterization – FM2/FM3 Impact on level 2 products
GOME-2 FM3 Metop-A
GOME-2 FM2 Metop-B
When introducing an empirical correction for the orbital change of the spectral resolution (FWHM) one can flatten out the currently observed RMS fit values.
Courtesy Faiza and Richter, UIP Bremen

14. Slit function characterization – FM2/FM3 Preliminary conclusions
GOME-2 FM3 Metop-A
GOME-2 FM2 Metop-B
The change in spectral resolution, as observed via the FWHM from spectral light source lines and Fraunhofer lines, is highly correlated with the change in the optical bench temperatures at all time scales: long-term, seasonal, orbital
For the seasonal and orbital variations the optical bench temperature and the FWHM are highly, positively correlated, i.e. for an decreasing OB temperature we observe a decreasing FWHM.
For the long-term temperature change, however, the FWHM change and the OB temperature change are anit-corelated.
Independent of the sign of the correlation, a changing spectral resolution may have a substantial effect on the level-2 retrieval quality depending on the spectral region and the absorber

15. Slit function characterization – FM2/Metop-B Commissioning level-1b – level-2 fit results
GOME-2 FM2 Metop-B
Fit residual peaks near 316 and 323 nm for RAL slit functions reported by KNMI
- potentially introduced by ghost fitting procedure (TBC)
Not present in TNO key-data slit functions

16. Is signal degradation a problem? – Yes, but....
GOME-2 / Metop-A degradation
Impact on level-2 products
GOME-2 FM3 Metop-A
Degradation predominantly affects fit residuals and scatter
Retrieved values are less or not affected
Fitting residuals increase over time
Effect is largest in channel 2, but NO2 is also affected
The same is true for other absorbers (SO2, HCHO, CHOCHO)
All operational products of GOME-2 / Metop-A are still within specifications
Is signal degradation a problem? – Yes, but....
Study by:
S. Dikty and A. Richter, IUP Bremen
See Level 2 report on the impact of degradation on level 2 products:
> Data & Products > Resources > EPS Product Validation Reports

17. Do we have an Etalon correction problem?
Instrument degradation (Metop-B / FM2) SMR ratio with respect to February 2007 – R2 campaign
GOME-2 FM3 Metop-A
Do we have an Etalon correction problem?
31st August 2009 (before 2nd TT)
30th October 2009 (after 2nd TT)
31st July 2011
relative to February 2007

18. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum at 311 nm (FPA & PMD)
GOME-2 FM3 Metop-A
FPA-SMR smoothed (black line) with PMD spectral response function.
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

19. Goniometry: Angular dependence for Solar Measurements (AIRR) Comparison between current key-data and high res. elevation angle grid
Band 3 solar signals at 420 nm
GOME-2/Metop-A
raw
calibrated
key-data
Solar Elevation angle
Solar Elevation angle
Key-data – angle resolution
In-flight derived values with increased angular resolution

20. Of relevance also for other current and future missions!
Goniometry: Angular dependence for Solar Measurements (AIRR) Comparison between current key-data and high res. elevation angle grid
GOME-2 FM3 Metop-A
The Angular dependence of irradiance on the diffuser in elevation and solar azimuth I0(f,e) is
difficult to measure on-ground (long-measurement period / in vacuum)
but one can derive it from in-flight data
1 year of in-flight data needed
FM3 on-ground
key-data
In-flight data
Of relevance also for other current and future missions!

21. GOME-2 FM3 Metop-A
Goniometry: Improved AIRR measurements for FM-2 TNO FM2 delta calibration campaign (Kenter et al.)
GOME-2 FM2 Metop-B
SAA: 0.5 resolution (317 to 333)
Elevation: 0.1 resolution (-1.5 to 1.5)
Similar to L1-processor angle fine-grid as defined in initialisation file!
FM3 Metop A
Original angular resolution
FM2 Metop B
Higher angular resolution

22. Goniometry: Angular dependence for Solar Measurements (AIRR) Comparison between current key-data and in-orbit derived data Angular domain – azimuth angle at 311 nm
GOME-2 FM3 Metop-A
FM3 on-ground key-data
FM3 in-flight data
In-flight data
The Angular dependence of irradiance on the diffuser in elevation and solar azimuth I0(f,e) is
difficult to measure on-ground (long-measurement period / in vacuum)...
...and can lead to artefacts in the long-term time-series of reflectances!

23. Goniometry: Angular dependence for Solar Measurements (AIRR) Application of in-orbit derived slit-function 260 and 330 nm
GOME-2 FM3 Metop-A

24. Goniometry: Angular dependence for Solar Measurements (AIRR) Application of in-orbit derived slit-function 450 and 745 nm
GOME-2 FM3 Metop-A

25. Goniometry: Angular dependence for Solar Measurements (AIRR) Application of in-orbit derived slit-function 745 nm
GOME-2 FM3 Metop-A

26. Goniometry: Angular dependence for Solar Measurements (AIRR) Application of in-orbit derived slit-function PMD-S band 12
GOME-2 FM3 Metop-A

27. Goniometry: Angular dependence for Solar Measurements (AIRR) Application of in-orbit derived slit-function PMD-S band 8
GOME-2 FM3 Metop-A

28. Goniometry: Angular dependence for Solar Measurements (AIRR) Comparison between current key-data and in-orbit derived data Spectral domain – Channel 1
GOME-2 FM3 Metop-A
FM3 in-flight data
FM3 on-ground key-data
The Angular dependence of irradiance on the diffuser in elevation and solar azimuth I0(f,e) is
difficult to measure on-ground (long-measurement period / in vacuum)...
...and can lead to artefacts in the spectral domain of the solar mean reference measurements!

29. Goniometry: Angular dependence for Solar Measurements (AIRR) Application for SMR spectrum in Jan/Feb 2007
GOME-2 FM3 Metop-A
New In-flight ARR
Reference

30. Goniometry: Angular dependence for Solar Measurements (AIRR) Application for SMR spectrum in Jan/Feb 2007
GOME-2 FM3 Metop-A
New In-flight ARR vs reference

31. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum
GOME-2 FM3 Metop-A
Reprocessed signals R2/NRT PPF 5.3 until October 2013
relative to February 2007

32. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum
GOME-2 FM3 Metop-A
Reprocessed signals R2/NRT PPF 5.3 until October 2013
relative to February 2007

33. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum
GOME-2 FM3 Metop-A
PMD-P
PMD-S
Reprocessed signals R2/NRT PPF 5.3 until October 2013
relative to February 2007

34. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum at 311 nm (FPA & PMD)
GOME-2 FM3 Metop-A
FPA-SMR smoothed (black line) with PMD spectral response function.
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

35. GOME-2 Metop-A Long-term throughput changes
Solar Mean Reference (SMR) spectrum at 570 nm (FPA & PMD)
GOME-2 FM3 Metop-A
FPA-SMR smoothed (black line) with PMD spectral response function.
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

36. GOME-2 Metop-A Long-term throughput changes
On-board calibration sources at 311 nm (FPA)
GOME-2 FM3 Metop-A
FPA-cal sources
smoothed with PMD spectral response function where indicated.
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

37. GOME-2 Metop-A Long-term throughput changes
On-board calibration sources at 570 nm (FPA)
GOME-2 FM3 Metop-A
FPA-cal sources
smoothed with PMD spectral response function where indicated.
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

38. GOME-2 Metop-A Long-term throughput changes
On-board calibration ETALON (FPA)
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

39. GOME-2 Metop-A Long-term throughput changes
On-board calibration ETALON (FPA)
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

40. GOME-2 Metop-A Long-term throughput changes
On-board calibration ETALON (PMDs)
GOME-2 FM3 Metop-A
PMD-P
PMD-S
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

41. GOME-2 Metop-A Earthshine degradation until August 2011
Sahara – 311nm – relative to mean of 2007
GOME-2 FM3 Metop-A
Earthshine Sahara
Normalised to 2007
Every 2nd scanner angle position is used (coloured solid lines)
Solar Mean Reference (black dashed line)
Low outliers are due to interfering narrow scan
R2 campaign
Jan 2007 – Aug 2011

42. GOME-2 Metop-A Reflectivity degradation
Sahara – at 312 nm – before and after 2nd throughput test
GOME-2 FM3 Metop-A
Earthshine Sahara
Every scanner angle position is shown
Rates in %/year
R2 campaign
Jan 2007– Jan 2012
Before Sep. 2009
After Sep. 2009

43. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
320 nm
Solar Reference
Earthshine
Reflectivity
Model/Fit-Results

44. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
570 nm
Earthshine &
Reflectivity
over
viewing angle

45. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
325/340/380 nm
Reflectivity degradation

46. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
325/340/380 nm
Reflectivity degradation
Empirical degradation correction from AAI level-2,
Tilstra et al., AAI Reprocessing ATBD, 2014.

47. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
325 nm
Reflectivity degradation

48. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
340 nm
Reflectivity degradation

49. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
380 nm
Reflectivity degradation

50. GOME-2 Metop-A degradation component modelling
Sahara at 340 nm – temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
380 nm
Reflectivity degradation
Empirical degradation correction from AAI level-2,
Tilstra et al., AAI Reprocessing ATBD, 2014.

51. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
2007
2008
2009
2011
Spectra from
modelled trend results
Spectrally smoothed model trend results

52. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
2007
2008
2009
2011
Spectra from
modelled trend results
Spectrally smoothed model trend results

53. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
2007
2008
2009
2011
Spectra from
modelled trend results
Spectrally smoothed model trend results

54. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
2007
2008
2009
2011
Spectra from
modelled trend results
Spectrally smoothed model trend results

55. GOME scan mirror contribution
Adapted SRON GOME-1 model results for GOME-2
GOME ERS-2
Scan mirror degradation
Adapted to GOME-2 from GOME-1 in spectral and temporal space
Model data provided by Snel and Krijger, SRON

56. GOME-2 scan mirror contribution vs instrument degradation
SMR and scan mirror contribution
GOME-2 FM3 Metop-A
Scan mirror and instrument degradation
Scan mirror model data based on GOME-1 provided by Snel and Krijger, SRON

57. GOME-2 instrument degradation
Hypothesis by the ESA/EUMETSAT/Industry GOME-2 tiger team
Arathene out-gassing by conformal coatings.
Hyposesis posed by the
“ESA/EUMETSAT/Industry GOME-2 tiger team
on instrument degradation.”
Arathene absorption spectra
“Peak at 310 nm corresponds to a more volatile component in the Arathene, which is effectively removed from the conformal coating by the bake-out process which is applied in the “real instrument PCBs”
Scan mirror model data based on GOME-1 provided by Snel and Krijger, SRON

58. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
2007
2008
2009
2011
Spectra from
modelled trend results
Spectrally smoothed model trend results

59. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– Jan 2012
Diffuser+Mirror
Arathene+Mirror

60. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A

61. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A

62. GOME-2 Metop-A degradation component modelling
Sahara – spectral domain at various periods in time
GOME-2 FM3 Metop-A

63. Modelled Earthshine degradation Modelled Solar Path degradation
GOME-2 Metop-A degradation component modelling
Sahara – spectral and temporal domain
GOME-2 FM3 Metop-A
Modelled Earthshine degradation
Modelled Solar Path degradation
800 nm
240 nm
Feb 2007
June 2013
Feb 2007
June 2013
R2 campaign Jan 2007– June 2013

64. GOME-2 Metop-A degradation component modelling
Sahara reflectivity – spectral and temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– June 2013
800 nm
Earthshine Trend
240 nm
Feb 2007
June 2013

65. GOME-2 Metop-A degradation component modelling
Sahara reflectivity – spectral and temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– June 2013
800 nm
Reflectivity Trend
240 nm
Feb 2007
June 2013

66. GOME-2 Metop-A degradation component modelling
Sahara reflectivity – spectral and temporal domain
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– June 2013
800 nm
Reflectivity Trend
240 nm
Feb 2007
June 2013

67. GOME-2 Metop-A degradation component modelling
Impact on level-2 using degradation correction
GOME-2 FM3 Metop-A
R2 campaign
Jan 2007– June 2013
Reflectivity Trend

68. Instrument degradation Comparison Metop-B/A - first months in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A - first months in orbit
GOME-2 FM2 Metop-B
Degradation over four month in-orbit covering the same in-orbit lifetime!
122 Days!
Metop-A
Metop-B
FM2 (Metop-B) degrades roughly in the same way as FM3 (Metop-A) except for channel 2.
...reason yet unkown!

69. Instrument degradation Comparison Metop-B/A - first year in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A - first year in orbit
GOME-2 FM2 Metop-B
Degradation after one year in-orbit covering the same in-orbit lifetime!
365 Days!
Metop-A
Metop-B
FM2 (Metop-B) degrades roughly in the same way as FM3 (Metop-A) except for channel 2.
...reason yet unkown!

70. Instrument degradation Comparison Metop-B/A – first 1.5 years in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A – first 1.5 years in orbit
GOME-2 FM2 Metop-B
Degradation after 1.5 years in-orbit covering the same in-orbit lifetime!
547 Days!
Metop-A
Metop-B
FM2 (Metop-B) degrades roughly in the same way as FM3 (Metop-A) except for channel 2.
...reason yet unkown!

71. Instrument degradation Comparison Metop-B/A - first months in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A - first months in orbit
GOME-2 FM2 Metop-B
PMD-P
PMD-S
Metop-A
Metop-B
122 Days!
Degradation over four month in-orbit covering the same in-orbit lifetime!

72. Instrument degradation Comparison Metop-B/A - first year in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A - first year in orbit
GOME-2 FM2 Metop-B
PMD-P
PMD-S
Metop-A
Metop-B
365 Days!
Degradation over 1 year in-orbit covering the same in-orbit lifetime!

73. Instrument degradation Comparison Metop-B/A - first 1.5 years in orbit
GOME-2 FM3 Metop-A
Instrument degradation Comparison Metop-B/A - first 1.5 years in orbit
GOME-2 FM2 Metop-B
PMD-P
PMD-S
Metop-A
Metop-B
547 Days!
Degradation over 1.5 years in-orbit covering the same in-orbit lifetime!

74. GOME-2 Metop-A/B Long-term throughput changes
GOME-2 FM3 Metop-A
GOME-2 Metop-A/B Long-term throughput changes
On-board calibration sources at 311 nm (FPA)
GOME-2 FM2 Metop-B
FPA-cal sources
smoothed with PMD spectral response function where indicated.
Metop-A
R2 campaign
Jan 2007 – Oct 2007
Metop-B
OPS
Jan 2013 – Oct 2013

75. GOME-2 Metop-A/B Long-term throughput changes
GOME-2 FM3 Metop-A
GOME-2 Metop-A/B Long-term throughput changes
On-board calibration sources at 311 nm (FPA)
GOME-2 FM2 Metop-B
FPA-cal sources
smoothed with PMD spectral response function where indicated.
Metop-A
R2 campaign
Jan 2007 – Oct 2007
Metop-B
OPS
Jan 2013 – Oct 2013

76. GOME-2 Metop-B Long-term throughput changes
On-board calibration sources at 745 nm (FPA)
GOME-2 FM2 Metop-B
Solar mean reference
Metop-B
OPS
December July 2014

77. Earthshine Trend/Forecast
GOME-2 degradation component modelling
Signal level prediction – Based on GOME-2 Metop-A Degradation model v0.9
GOME-2 FM3 Metop-A
Earthshine Trend/Forecast
Solar Trend/Forecast

78. GOME-2 degradation component modelling
Signal level prediction
GOME-2 FM3 Metop-A
Reflectivity
Trend/Forecast

79. Earthshine Trend/Forecast
GOME-2/Metop-B degradation component modelling
Signal level prediction – Based on GOME-2 Metop-A Degradation model v0.9
GOME-2 FM2 Metop-B
Earthshine Trend/Forecast
Solar Trend/Forecast

80. GOME-2/Metop-B degradation component modelling
Signal level prediction
GOME-2 FM2 Metop-B
Reflectivity
Trend/Forecast

81. Earthshine Trend/Forecast
GOME-2/Metop-C degradation component modelling
Signal level prediction – Based on GOME-2 Metop-A Degradation model v0.9
GOME-2 FM1 Metop-C
Earthshine Trend/Forecast
Solar Trend/Forecast

82. GOME-2/Metop-C degradation component modelling
Signal level prediction
GOME-2 FM1 Metop-C
Reflectivity
Trend/Forecast

83. GOME-2 Metop-A diffuser stability
Normalised signal of spectral line source (SLS) over diffuser - monthly
GOME-2 FM3 Metop-A
Diffuser signal trend
Slight increase
i.e. Slight diffuser degradation detected!
<10% in 7 Years
R2 campaign
Jan 2007 – Jan 2012
OPS phase (same PPF 5.3)
Jan 2012 – Oct 2013

84. GOME-2 / Metop-A End of Life scenario
Loss of solar measurments
GOME-2 FM3 Metop-A

85. GOME-2 / Metop-A End of Life scenario
Loss of solar measurements
GOME-2 FM3 Metop-A

86. GOME-2 / Metop-A End of Life scenario
Loss of solar measurements
GOME-2 FM3 Metop-A
Double OOP in Autumn 2015
Gap1
(beginning 2017)
Days
Gap2 (end 2017/ beginning 2018)
Gap3
(end 2018/ continuing in 2019)
Total Number of Days with no GOME Sun Visibility
Burn Start at Eclipse Entry
2017/01/23-
2017/02/22 31
2017/12/ /03/17 79
2018/11/13-
2019/01/01
(2019/05/02) 49
(171)
159
(281)
Burn Start at Eclipse Entry FOV + 0.5deg
2017/02/ /02/03 8
2018/01/02-
2018/03/15 73
2018/11/21-
(2019/04/24) 41
(155)
122
(234)
Burn Start at Eclipse Entry -60s
2017/01/ /02/17 22
2018/01/01- 74
2018/11/23-
(2019/04/23) 39
(152)
135
(248)
Burn Start at Eclipse Entry -60s + 0.5deg(*) 67 20
(143) 87
(210)
Burn Start at Eclipse Entry -120s
2017/02/ /02/10
2018/01/ /03/12 68
2018/11/30-
(2019/04/16) 32
(138)
108
(214)
Burn Start at Eclipse Entry -120s + 0.5deg(*) 60 10
(132) 70
(192)

87. The end