Your browser does not seem to support JavaScript. As a result, your viewing experience will be diminished, and you have been placed in read-only mode.
Please download a browser that supports JavaScript, or enable it if it's disabled (i.e. NoScript).
The average amount of solar radiation that reaches the earths upper atmosphere on a surface perpendicular to the suns rays; equal to 1353 Watts per square meter or 492 Btu per square foot.
Share your knowledge with the community
Browse our collection of 300,000+ community-written definitions
