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.
Temperature | Pressure | Radiation | Aerosols | Air Quality | Clouds | Surface
All Unit Definitions | Full Science Glossary | The Metric System

a unit of measure used for atmospheric pressure. Standard atmospheric pressure is 1013.25 millibars, or mb, so this offers a very sensitive scale: 1 millibar represents a one tenth of one percent change in atmospheric pressure.  
More about surface pressure units