Additional Information

MSG RGB 321 15 Jan 06

Here is some additional information about the natural color RGB.

Bare land (including desert) is brownish red, representing the very strong contribution from the 1.6 µm near-infrared channel in red and the weaker contribution from the 0.8 µm visible channel in green. There is little contribution from the 0.6 µm visible channel in blue.

Vegetation, including much of the land over Europe, is highly reflective in the 0.8 µm visible channel, which produces the green vegetative shading in the product.

Water phase clouds are very reflective in all three channels and combine to produce white water phase clouds.

You probably noticed that snow cover is cyan. That’s because snow is highly reflective in the 0.8 µm and 0.6 µm visible channels. When assigned to be green and blue, the colors combine to produce cyan. Although this is unnatural in appearance, non-intuitive colors are common in RGBs and easy to interpret if you know the color scheme.

Ice clouds are also cyan.

Finally, water is dark because of the minimal reflection and hence contribution from all three channels.

What would happen if one of the less than optimal combinations was used for the natural color RGB? You would get used to it, and learn to interpret it correctly. But the goal is to create products that provide useful information, and communicate quickly to forecasters.