Training Module on METOP AVHRR RGB Images

• Chapter II: AVHRR Night Microphysics RGB


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• Aim
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• Physical Basis
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• How to create Night Microphysics RGB images
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• Typical Colors
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• Examples of Interpretation
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• Benefits and limitations
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• Comparison of AVHRR and SEVIRI Night Microphysics RGB images
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• Exercises

Examples of interpretation

Three cases are shown with annotations to demonstrate the proper interpretation of different surface and cloud types in Night Microphysics RGB images (Figs. 10 - 12).

Figure 10: AVHRR Night Microphysics RGB on 14 December 2015 at 00:52 UTC

Figure 11: AVHRR Night Microphysics RGB on 14 December 2015 at 02:33 UTC

Note that thick fog/low level clouds (stratus) appear green in the case of small water droplets or gray with a pinkish tone in the case of large droplets. Thin fog and stratus also appear gray with a pink tone.

Figure 12: AVHRR Night Microphysics RGB on 24 January 2016 at 20:28 UTC