In the GOES-13 Visible channel, there seems to be a morning/afternoon asymmetry in the data. I'm wondering what might cause this.
In this example data, the morning is the lower branch, and the afternoon is the upper branch. The y-axis is the pixel level (0..255), the x-axis is the Sun's local altitude above the horizon. The location is the Gulf of St. Lawrence, on the east coast of Canada.
Latitude +46.94N, longitude -63.21W (not far from the center of the images below.)
Morning, 10am local time:
Afternoon, 4pm local time: