Sunrise over Streatham

Judging from earlier Blips, and my Twitter stream, I was far from alone in photographing the sunrise over South London this morning. What interested me about this shot is that the sun is illuminating the two layers of cloud very differently. The (I assume) lower aircraft vapour trail is white, while the higher ones are red.

I assume it's down to different degrees of Rayleigh scattering, but I'm still trying to work out the physics of it.

This represents my best attempt at tweaking the colour balance in Photo Editor; the phone's camera produced something much more purple.