This is one of those studies when an ah ha moment happens. Why are colours of the sunrise so vibrant? Well this is what i found out:

It is the first time "light" is being introduced to the dark of night, light being

colour & not value!  With the absence of light all we are left with is grey. So as a painter in search of light i discover that in a low saturation field i am able to depict light which is colour easier. I'm also fascinated in when dealing with neutral greys how they are affected when adding colour. Last is the analogous harmony which harmonizes the scene. Good fun, three studies below with varying levels of pushing colour into neutral grey.