Mid-level clouds depict in pastel red colours in the Day Microphysics RGB images.
Mid level clouds in the Day Microphysics RGB depict in pastel red colours, i.e. they include a high amount of white. All 3 colour beams contribute with approximately the same intensity. Depending on cloud microphysical processes, the red colour beam dominates more or less over the other colours.
Ice crystals ontop of mid-level clouds absorb much of the short wave solar radiation at 3.9 micrometer. Hence the red and the blue colour is of higher importance than the green colour beam.
The contribution of the blue colour beam depends on the amount of measured IR10.8 radiation and diminishes with decreasing temperatures
Mid level clouds with containing ice crystals can be seen in the Day Microphysics RGB image below (green cercle). These clouds are located at the rear side of a cold front. The pastel green clouds surrounding them are pure water clouds.
Day Microphysics RGB from 7 February 2016, 12:00 UTC
Explanation of the pastel red colour of mid-level clouds in the Day Microphysics RGB (see the recipe):
All 3 colour beams contribute with about the same intensity in case of mid-level clouds. Nevertheless, the red and blue colour outperforms the green colour contribution as the latter is weak when the cloud contains ice crystals. The blue contribution gets weaker than the red contribution when the cloud top temperature diminishes.