air mass
- noun
- /ɛr mæs/
- Specialized
- Temperature decreases with altitude and here you get air masses that rise and fall and you get vertical mixing.
- tropical air masses
Examples
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During the summer, ocean breezes and winds from the mountain ridges can cool down the coastal regions, whereas the Fraser Valley can trap air masses and create a relatively hot zone (Oke and Hay 1994).
Academic text (2016) -
The high pressure that brought us this beautiful air mass will slowly drift down to our southeast.
Blog text (26) -
It's expected that some sort of air mass may be moving down from Canada.
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A large air mass is moving down from Canada.
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There's always an air mass moving down from Canada.
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The rotating air mass creates a high-pressure system throughout the region.
Academic text (2003) -
One station is affected by maritime polar air masses; the other, continental tropical.
Blog text (22) -
That'll be followed by a bitter cold, arctic air mass and high winds.
Fiction book (1993) -
Air near the equator is heated and ascends high into the atmosphere due to its buoyancy within the cooler air masses that surround it.
Academic text (2005) -
Forecasters expect snow Monday morning as a colder air mass arrives just in time for the workweek.
Surface Forms
Morphology
The compound is transparently built from 'air' (the atmosphere/gases) + 'mass' (a large body), so a B1 learner who knows both words can infer it refers to a large body of air. While meteorological details (uniform temperature/humidity) are technical, the core idea of a sizable volume or body of air is directly derivable and cross-linguistically common.
Etymology
Air mass comes from the idea of a large block of air, a moving mass that has 'the same temperature and moisture'. Imagine a giant invisible balloon of air moving over a region, and that's why an air mass helps explain changes in the weather.