Version 1.0, 30 June 2004

APPLICATIONS OFMETEOSAT SECOND GENERATION (MSG)RGB IMAGES: PART 06

NOT RECOMMENDED RGBCOLOUR COMPOSITES

Author:Author: Jochen Kerkmann (EUMETSAT)Jochen Kerkmann (EUMETSAT)kerkmann@eumetsat.dekerkmann@eumetsat.de

Version 1.0, 30 June 2004

PART 6:

NOT RECOMMENDED RED-GREEN-BLUE COLOUR COMPOSITES

Version 1.0, 30 June 2004

• 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. IR10.8 provides cloud top temperature, VIS0.6 provides cloud optical thickness, VIS0.8 provides "greeness" of vegetation etc…)

• It does not make sense to combine channels that represent the same physical property!

Channel Selection

Version 1.0, 30 June 2004

VIS0.6: optical thickness and amount of cloud water and iceVIS0.8: optical thickness and amount of cloud water and ice

"greeness" of vegetationNIR1.6, IR3.9r: particle size and phaseWV6.2, WV7.3: mid- and upper level moistureIR8.7, IR10.8, IR12.0: top temperature

IR8.7 - IR10.8: phase and optical thicknessIR12.0 - IR10.8: optical thicknessIR3.9 - IR10.8: optical thickness, phase, particle sizeIR13.4 - IR10.8: top heightWV6.2 - IR10.8: top height, overshooting tops

(Cloud) Physical Properties representedby the MSG Channels

Version 1.0, 30 June 2004

Not Recommended Schemes forRGB Image Composites

RGB 01,02,09i: although known from AVHRR, this combination duplicatesthe visible information. It is better to create RGB 12,12,09 instead.

RGB 04i,09i,10i: also known from AVHRR (night-time), but duplication of cloudtop temperature information. It is better to use the RGB10-09,09-04,09 during night-time.

RGB 07i,09i,10i: combines three times the top temperature information; the resultingimage will not have many colours. It is better to use the brightnesstemperature differences (e.g. RGB 10-09,09-07,09).

RGB 05i,08i,11i: combines three sounding channels, which are not useful forcloud observation. Again, it is better to combine these channels withother channels to get relevant physical properties (e.g 05-09 (topheight); 05-06 (top height, WV structure); 06-11 (SO2concentration)).

1.

2.

3.

4.

Version 1.0, 30 June 2004

1. Not Recommended RGB 01,02,09

MSG-1, 13 June 2003, 14:00 UTC

RGB 01,02,09i (not recommended) RGB 12,12,09i (recommended)

Version 1.0, 30 June 2004

2. Not Recommended RGB 04i,09i,10i

MSG-1, 03 February 2004, 03:00 UTC

RGB 04i,09i,10i (not recommended) RGB 10-09,09-04,09 (recommended)

Version 1.0, 30 June 2004

3. Not Recommended RGB 07i,09i,10i

MSG-1, 26 May 2004, 12:00 UTC

RGB 07i,09i,10i (not recommended) RGB 10-09,09-07,09 (recommended)

Version 1.0, 30 June 2004

4. Not Recommended RGB 05i,08i,11i

MSG-1, 08 September 2003, 12:00 UTC

RGB 05i,08i,11i (not recommended) RGB 05-06,04-09,03-01 (recommended)