Compared to the size of the Earth , the atmosphere is a thin shell. The thin atmosphere lighted by the setting Sun.
Water is a minor, but very important constituent of the Earth's atmosphere.
This image taken by an instrument onboard the Upper Atmosphere Research Satellite shows water vapor content over the Pacific Ocean during the El Ni o event of October, 1997. Red indicates high water content and blue is low. High atmospheric moisture corresponds to warmer water. The result was that the heavy rainfall that usually stays west toward Indonesia instead hit the west coast of North America.