Digital Light & Color

There are two problems here: first is a rather bad color cast, and second is low contrast. To attack the first, I used RGB curves (which also had the effect of increasing contrast.) I set the black and white points of each channel at the ends of the main lump of the histogram and applied these at 50...

In a hazy picture the red channel often contains the most detail, so I created this version by replacing the HSL L channel with the red channel. (Specifically, by using Color->Extract Channels to get R, H, and S followed by Gray->Combine Channels.) It isn't meant to be a final version, just a better...