Understanding Scientific Units

Earth science data parameters have very specific definitions and units. The links below will access some definitions for science parameter units by the topic of interest.
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All Unit Definitions | Full Science Glossary | The Metric System

J
joule:
a standard unit of energy (radiation) or work (mechanics). For energy, one joule is equal to one watt second.   unit relationships
Image courtesy NASA
S
steradian:
a standard unit of solid angle. One steradian is the solid angle made at the center of a sphere by an area on the surface of the sphere equal to the square of the sphere’s radius.  
Illustration of a steradian
W
watt:
a standard unit of power. In radiation studies, watts are used to quantify the flux of shortwave or longwave energy across a unit area such as Earth’s surface (watts per meter squared).   unit relationships
Image courtesy NASA