Hyphens in noun clusters

Science writing employs hyphens more often than regular writing. In scientific writing, writers often refer to specific ideas or objects that would be too complex or cumbersome to describe completely every time you mention them.

Noun clusters are groups of nouns that act as one noun in your sentence. A hyphen is used to indicate that a noun is acting as an adjective to modify the subsequent noun:

• Cold-air damming led to freezing rain.
• Surface stations measured sea-level pressure.
• Upper-level temperatures indicated a strong subsidence inversion.

Note that air and level are both nouns that are used to modify the meaning of words like damming, pressure, and temperatures.

The hyphen is not used when the two words stand on their own:

• Cold air leads to lakes freezing in the winter time.
• Pressure was reduced to sea level.
• No front was observed at upper levels.

If you look carefully at any AMS article, you will notice more examples of this convention. When in doubt, check AMS publications to see how the convention is used.

As always, be careful when using hyphens as mistakes can change the entire meaning of a sentence.