This is an image of the sunrise from space over the South China Sea. An astronaut would see something like this; clearly defined bands of color through the atmosphere as the sun rises. High-peaking cumulus clouds, topping out in anvil-head cirrus can be seen as black shadows against the sunlit horizon. The brightness of the colors in the atmosphere in this photograph is due to the amount of dust in the atmosphere. More dust is found in near the equator. There are various sources for such upper level dust. Many dust storms in Africa and ash clouds from major volcanic eruptions are two reasons.
Courtesy LPI/NASA