A large body of air with the same temperature and
humidity characteristics. Air masses are classified according to their origin.
The table gives the characteristics of the four kinds of air masses in North
America.
Name
Symbol Character Source
Continental polar cP
Cold, dry Canadian
arctic
Maritime polar mP
Cold, moist North Atlantic
and
Pacific
Continental tropical cT Warm, dry Mexico
and
south east
United
States
Maritime tropical mT
Warm, Caribbean
moist and South
Pacific
The movement of air masses controls the local
weather. The boundary between two
air masses is
called a front.
