One key advantage of the Nighttime Microphysics RGB is its ability to depict low-level cloud layers at night. These are marked by elevated red and green contributions within the RGB recipe, however a case from 6 April 2022 shows that not all low-level clouds look the same. Overnight a cold front was advancing southeastward through the central United States. Behind the cold front (Oklahoma, Kansas, Missouri, and Arkansas) we see that the stratus clouds are colored green-yellow, however, the stratus clouds ahead of the cold front (Texas, Louisiana, Mississippi, and Alabama) are light blue. The question is why?
While stratus clouds often have strong contributions from the red and green bands (indicating thick, water clouds), the relative blue contribution from the Channel 13 Clean-IR Brightness Temperature (10.3 um) can highlight the relative temperature differences of stratus clouds. See the abbreviated RGB recipe for the Nighttime Microphysics RGB below.
To see this effect for yourself, you can compare the Nighttime Microphysics RGB to the Clean-IR Brightness Temperature imagery using the slider tool below. Note the position of the cold front (via the surface observations), where the colors of the stratus clouds change in the Nighttime Microphysics RGB, and the higher/lower Clean-IR Brightness Temperatures ahead/behind the cold front.
Kevin Thiel, OU CIWRO