Air mass classification involves three letters. The first
letter describes its moisture properties: continental air
masses (c) and maritime air masses (m). The second
letter is its source region: tropical (T), polar (P), arctic or
Antarctic (A), monsoon (M), Equatorial (E), and superior
(S) air. For instance, an air mass originating over the
desert southwest of the United States in summer may
be designated "cT"and an air mass originating over
northern Siberia in winter may be indicated as "cA." The
stability of an air mass may be shown using a third
letter, either "k" (air mass colder than the surface below
it) or "w" (air mass warmer than the surface below it).
In meteorology, an air mass is a volume of air defined
by its temperature and water vapor content. Air masses
cover many hundreds or thousands of miles, and adapt
to the characteristics of the surface below them. Which
statement INCORRECTLY describes air masses.
Tropical air masses form closer to the equator
where the air is warm.
Maritime air masses form over water and dry out as
they lose water vapor to the water below it.
Continental air masses form over land and are dry
as they travel across the land below.
Polar air masses form far from the equator where
the air is cold