NASA
Nasa Earth Observatory: Clouds in a Clear Sky
This article introduces the different layers of the atmosphere and the clouds that are formed there. Scientists use instruments such as the SAGE 11 that help to measure amounts of sunlight, water vapor, and other conditions that affect...
NASA
Nasa Earth Observatory: Every Cloud Has a Filthy Lining
This article discusses what clouds are made of, including the dirty particles in them called aerosols. Learn about the natural and man-made sources of aerosols.