Have you tried toning down the brightness? In all my playing around, I've concluded that for the most part (there is a little crossover) brightness controls the light from the sky, ambience controls ambient light obviously, but this affects entities and the ground. Surface level pretty much just controls the ground. Each affects others somewhat, but those are the gist of them. If you turn down the brightness and turn up the ambience, it should look better. You may not even need to adjust the ambience from where it is in that screenshot. If necessary, you can tone down surface levels and ambience levels further by adjusting the individual channels by the same amounts. Also, don't forget the contrast! If all else fails, a really cloudy sky can help!
MAME Cab PC: i7 4770@3.4Ghz (passmark 9945), 12GB RAM, Win 8.1/64, GeForce GTX645 (passmark 1898); Shiny new laptop: i7 4800MQ@2.7Ghz (passmark 8586), 16GB RAM, Win 8.1/64, GeForce GTX870M (passmark 3598); Old laptop: i5@2.3Ghz, 8GB RAM, Win 7/64, Intel 3000 graphics