1. Best practices for RGB compositing of multi-spectral imagery
Proposed standard RGB composites – SEVIRI based
RGB composite samples
(supplement to APPENDIX A)

2. AIR MASS
(night & day)
6.2 (inverted)

3.
6.2i
MSG-1, 7 January 2005, 03:00 UTC

4. AIR MASS Example: Advection Jet
MSG-1, 7 January 2005, 22:00 UTC

5. AIR MASS Global View
Note: warm air masses seen at a high satellite viewing angle appear with a bluish colour (limb cooling effect) !
MSG-1
19 April 2005
10:00 UTC

6. AIR MASS: Interpretation of Colours
Thick, high-level clouds
Thick, mid-level clouds
Thick, low-level clouds
(warm airmass)
Thick, low-level clouds
(cold airmass)
Jet (high PV) Cold Airmass Warm Airmass Warm Airmass
High UTH Low UTH

7. DUST
(night & day)
10.8

8.
10.8
MSG-1, 3 March 2004, 01:00 UTC

9. DUST Example
MSG-1, 25 June 2003, 10:00 UTC

10. DUST
Global View
MSG-1
22 January 2004
12:00 UTC

11. DUST: Interpretation of Colours for High-level Clouds
Cold, thick, high-level clouds
Thin Cirrus clouds
Contrails
Ocean Warm Desert Cold Desert Warm Land Cold Land

12. DUST: Interpretation of Colours for Low/Mid-level Clouds
Thick, mid-level cloud
Thin, mid-level cloud
Low-level cloud
(cold atmosphere, Europe)
Low-level cloud
(warm atmosphere, Africa)
Dust Storm
Ocean Warm Desert Cold Desert Warm Land Cold Land

13. NIGHT MICROPHYSICS
10.8

14. NIGHT MICROPHYSICS Example: Fog
MSG-1, 14 March 2005, 00:00 UTC

15. NIGHT MICROPHYSICS Example: Cb
MSG-1, 19 April 2005, 03:15 UTC

16. NIGHT MICROPHYSICS Example: Cirrus
MSG-1, 18 March 2005, 00:00 UTC

17. NIGHT MICROPHYSICS Global View
MSG-1
3 February 2004
03:00 UTC

18. NIGHT MICROPHYSICS: Interpretation of Colours for High-level Clouds
Cold, thick, high-level cloud
Very cold (< -50°C), thick, high-level cloud
Thin Cirrus cloud
Ocean Land

19. NIGHT MICROPHYSICS: Interpretation of Colours for Mid/Low-level Clouds
Thick, mid-level cloud
Thin, mid-level cloud
Low-level cloud
(cold atmosphere, Europe)
(warm atmosphere, Africa)
Ocean Land

20. 3.9 (solar part, CO2 corrected)
DAY MICROPHYSICS
(winter & summer)
0.8
3.9 (solar part, CO2 corrected)
IR10.8

21. 0.8
3.9solar
10.8
MSG-1, 8 September 2003, 12:00 UTC
Winter case

22. DAY MICROPHYSICS (winter) Example:
Severe Convection
MSG-1, 20 May 2003, 13:30 UTC

23. DAY MICRPHYSICS (winter) Example:
Ship Trails
MSG-1, 7 September 2003, 11:45 UTC

24. DAY MICROPHYSICS (winter) Example:
Fires
MSG-1, 7 September 2003, 11:45 UTC

25. DAY MICROPHYSICS (summer) Example:
Severe Convection
MSG-1, 13 June 2003, 12:00 UTC

26. DAY MICROPHYSICS: Physical Interpretation for Clouds
Red: Cloud depth and amount of cloud water and ice,
provided by the visible reflectance at 0.8 mm.
Green: Cloud particle size and phase, approximated by the 3.9 mm solar reflectance component.
Blue: Temperature, provided by the 10.8 mm channel.

27. DAY MICROPHYSICS: Interpretation of Colours for High-level Clouds
Thin Cirrus cloud
(large ice particles)
(small ice particles)
Deep precipitating cloud
(precip. not necessarily
reaching the ground)
- bright, thick
- large ice particles
- cold cloud
Deep precipitating cloud
(Cb cloud with strong
updrafts and severe
weather)*
- bright, thick
- small ice particles
- cold cloud
*or thick, high-level lee cloudiness with small ice particles
Ocean Veg. Land Fires / Desert Snow

28. DAY MICROPHYSICS: Interpretation of Colours for Mid-level Clouds
Supercooled, thick
water cloud
- bright, thick
- large droplets
Supercooled, thick
water cloud
- bright, thick
- small droplets
Supercooled thin water
cloud with large droplets
Supercooled, thin water
cloud with small droplets *
* or, in rare occasions,
thin Ci cloud with small
ice particles
Ocean Veg. Land Fires / Desert Snow

29. DAY MICROPHYSICS: Interpretation of Colours for Low-level Clouds
Thick water cloud
(warm rain cloud)
- bright, thick
- large droplets
Thick water cloud
(no precipitation)
- bright, thick
- small droplets
Thin water cloud with large droplets
Thin water cloud
with small droplets
Ocean Veg. Land Fires / Desert Snow

30. NATURAL COLOURS
1.6
0.8
0.6

31. NATURAL COLOURS Example: Snow
MSG-1, 18 February 2003, 13:00 UTC

32. NATURAL COLOURS: Vegetation
MSG-1, 23 June 2003, 15:00 UTC

33. NATURAL COLOURS: Desert
MSG-1, 3 February 2004, 11:30 UTC

34. NATURAL COLOURS Example: Low-level Water Clouds (St, Sc)
MSG-1, 03 February 2004, 11:30 UTC

35. NATURAL COLOURS Global View
MSG-1
19 April 2005
12:00 UTC

36. NATURAL COLOURS: Interpretation of Colours
High-level ice clouds
Low-level water clouds
Ocean Veg. Land Desert Snow

37. Samples of optional RGB composites

38. Ch.02
VIS0.8
Ch.03
NIR1.6
Ch.04r
IR3.9r
MSG-1, 24 February 2003, 11:00 UTC

39. DAY FOG-SNOW (winter) Example: Snow
MSG-1, 26 January 2004, 10:00 UTC

40. DAY FOG-SNOW (winter) Example: Low Clouds
MSG-1, 26 January 2004, 10:00 UTC

41. DAY FOG-SNOW: Interpretation of Colours for Thick Ice and Water Clouds
Deep precipitating cloud
(precip. not necessarily
reaching the ground)
- bright, thick
- large ice particles
Deep precipitating cloud*
- bright, thick
- small ice particles
*or thick, high-level lee cloudiness with small ice particles
Thick water cloud with large droplets
Thick water cloud
with small droplets
Ocean Veg. Land Desert Snow

42. DAY CONVECTIVE STORMS

43. DAY CONVECTIVE STORMS Example: Severe Convection
RGB 02,04r, RGB 05-06,04-09,03-01
(for comparison) better identification of young, severe storms
MSG-1, 13 June 2003, 12:00 UTC

44. DAY CONVECTIVE STORMS Global View
5 September 2004
15:00 UTC

45. DAY CONVECTIVE STORMS: Interpretation of Colours
Deep precipitating cloud
(precip. not necessarily
reaching the ground)
- high-level cloud
- large ice particles
Deep precipitating cloud
(Cb cloud with strong
updrafts and severe
weather)*
- high-level cloud
- small ice particles
*or thick, high-level lee cloudiness with small ice particles
Thin Cirrus cloud
(large ice particles)
Thin Cirrus cloud
(small ice particles)
Ocean Land

46. Best practices for RGB compositing of multi-spectral imagery
Improved spatial resolution of RGB composites through combination with HRV – SEVIRI based
(supplement to Appendix B)

47. Combining HRV with RGB composite
0.8
HRV
Sampling RGB composites at HRV resolution (blow up by factor 3) and overlaying them on HRV enhances the spatial resolution considerably (close to HRV). Colour scheme suffers somewhat but remains sufficiently clear – model of Swiss compromise! Proprortion for close-to-optimum mix for overlay is 60% HRV + 40% RGB.
0.8,1.6,3.9solar
HRV & 0.8,1.6,3.9solar