"O. Sami Saydjari" wrote:

Tim,

Chapter 1, section 1 of the AIM would seem to be most appropriate for
this question, and I have found no references to radar echoes. If you
have a pointer to the information that you think answers my question,
that would be helpful.

Please forgive my ignorance, but I do not know the acronym "IHB."
Please expand.

FAA Instrument Handbook



I have also tried Circular AC-00-6A, and did not find it.

I would also note that note of these sources is likley to answer the
questions of color mapping on a GDL-49/Garmin 430.

That is Garmin's responsibility to explain what their equipment does and
presents. Having said that, a pilot cannot be expected to assess the levels of
intensity to the same degree of discernment that a severe weather expert
sitting at a desk with a giant NEXRAD display does.

Green, yellow, and red where chosen for color radar displays based on the same
human factors used for traffic lights, and other safety signals.

Some folks used monochrome radar displays very successfully for many years.