Air mass — Science definition
A huge body of air that takes on a fairly uniform temperature and humidity from the surface it sits over for days at a time.
Where it is taught
- Air Masses, Fronts & Pressure — Atmosphere & Weather, Earth & Space Science, Grade 9
In use
Step outside and the air you feel might belong to a single enormous air mass — a body of atmosphere often hundreds of miles across that has parked over one kind of surface long enough to take on its temperature and moisture, becoming fairly uniform throughout.
Air Masses, Fronts & Pressure
Questions using air mass
Problem 1
- Cold and dry
- Cold and moist
- Warm and dry
- Warm and moist
Answer and explanation
Cold and dry
'Continental' means it formed over land (dry), and 'polar' means it formed at a cold latitude.
Problem 2
Hints
State what the supplied observations or conditions establish, and separate that from any assumption.
Answer and explanation
Temperature, humidity, origin region and movement provide important context.
Problem 3
- cold and dry
- warm and moist
- cold and moist
- warm and dry
Answer and explanation
warm and moist
An air mass takes on the temperature and humidity of the surface it forms over.
Problem 4
Answer and explanation
An air mass takes on the temperature and moisture of the surface it sits over for long enough — cold and dry over polar land, warm and moist over tropical ocean. Knowing where an approaching air mass formed therefore predicts what weather it brings, and knowing what it crosses on the way predicts how it will be modified, which is the basis of a forecast built from pressure maps.
Response criteria
- State a scientifically accurate conclusion.
- Show the data, mechanism, or calculation that supports it.
- Include units, conditions, or limits where relevant.