APPLICATIONS OF METEOSAT SECOND GENERATION MSG RGB IMAGES

APPLICATIONS OF METEOSAT SECOND GENERATION (MSG) RGB IMAGES: PART 06 NOT RECOMMENDED RGB COLOUR COMPOSITES Author: Version 1. 0, 30 June 2004 Jochen Kerkmann (EUMETSAT) kerkmann@eumetsat. de

PART 6: NOT RECOMMENDED RED-GREENBLUE COLOUR COMPOSITES Version 1. 0, 30 June 2004

Channel Selection • The selection of the channels to be combined in a RGB composite should be based on the physical properties represented by the channels (e. g. IR 10. 8 provides cloud top temperature, VIS 0. 6 provides cloud optical thickness, VIS 0. 8 provides "greeness" of vegetation etc…) • It does not make sense to combine channels that represent the same physical property! Version 1. 0, 30 June 2004

(Cloud) Physical Properties represented by the MSG Channels VIS 0. 6: VIS 0. 8: optical thickness and amount of cloud water and ice "greeness" of vegetation NIR 1. 6, IR 3. 9 r: particle size and phase WV 6. 2, WV 7. 3: mid- and upper level moisture IR 8. 7, IR 10. 8, IR 12. 0: top temperature IR 8. 7 - IR 10. 8: IR 12. 0 - IR 10. 8: IR 3. 9 - IR 10. 8: IR 13. 4 - IR 10. 8: WV 6. 2 - IR 10. 8: Version 1. 0, 30 June 2004 phase and optical thickness, phase, particle size top height, overshooting tops

Not Recommended Schemes for RGB Image Composites 1. RGB 01, 02, 09 i: although known from AVHRR, this combination duplicates the visible information. It is better to create RGB 12, 09 instead. 2. RGB 04 i, 09 i, 10 i: also known from AVHRR (night-time), but duplication of cloud top temperature information. It is better to use the RGB 10 -09, 09 -04, 09 during night-time. 3. RGB 07 i, 09 i, 10 i: combines three times the top temperature information; the resulting image will not have many colours. It is better to use the brightness temperature differences (e. g. RGB 10 -09, 09 -07, 09). 4. RGB 05 i, 08 i, 11 i: combines three sounding channels, which are not useful for cloud observation. Again, it is better to combine these channels with other channels to get relevant physical properties (e. g 05 -09 (top height); 05 -06 (top height, WV structure); 06 -11 (SO 2 concentration)). Version 1. 0, 30 June 2004

1. Not Recommended RGB 01, 02, 09 i (not recommended) RGB 12, 09 i (recommended) MSG-1, 13 June 2003, 14: 00 UTC Version 1. 0, 30 June 2004

2. Not Recommended RGB 04 i, 09 i, 10 i (not recommended) RGB 10 -09, 09 -04, 09 (recommended) MSG-1, 03 February 2004, 03: 00 UTC Version 1. 0, 30 June 2004

3. Not Recommended RGB 07 i, 09 i, 10 i (not recommended) RGB 10 -09, 09 -07, 09 (recommended) MSG-1, 26 May 2004, 12: 00 UTC Version 1. 0, 30 June 2004

4. Not Recommended RGB 05 i, 08 i, 11 i (not recommended) RGB 05 -06, 04 -09, 03 -01 (recommended) MSG-1, 08 September 2003, 12: 00 UTC Version 1. 0, 30 June 2004