1. Write “MT” where you
would find a Maritime
Tropical air mass.
Write “MP”
where you would find a
Maritime Polar air mass.
Write “CT”
where you would find a
Continental Tropical air
mass.
Write “CP”
where you would find a
Continental Polar Air
mass.
2. Which region is the probable source of the air mass labeled cP on the map?
a. central Canada
c. North Atlantic Ocean
b. southwestern United States d. Gulf of Mexico
3. You look at a newspaper and see that an “mP” air mass is moving towards to your
area. What type of air mass is coming? Which temperature and moisture
conditions would you expect from the “mP” air mass?
4. What is the difference between a “continental” air mass and a “maritime” air mass?
What is the difference between a “tropical” air mass and a “polar” air mass?
5. Large bodies of air located over a particular region acquire the attributed of temperature and humidity
characteristic of that region. A body of air that is relatively uniform in temperature and humidity is an air mass. While
temperature and pressure are used to characterize air masses, these measures also influence other weather
variables. For example, temperature and humidity affect air density. So air that is cold and dry tends to occur where
barometric pressure is high. Winds, in turn, are affected by the air-pressure gradient. Cloud cover and precipitation
are related to humidity. Therefore, when meteorologists characterize an air mass by its temperature and humidity
they may imply other weather variables as well.
Which two characteristics are used to classify air masses?
6. Based on the temperature and humidity of an air mass, the location where it originated can often be inferred. This
is known as the source region for the air mass. For example, a relatively cold, dry air mass moving from west to east
across New York State most likely came from central Canada. In central Canada, there is relatively little open water
and cooler temperatures prevail. An air mass that is warm and moist most likely originated over the South Atlantic
Ocean or the Gulf of Mexico. This kind of air mass is likely to bring lower air pressure with clouds and precipitation.
What are two differences between air masses that originate over central Canada and the Gulf of Mexico?
7. The terms continental and maritime are used to describe the humidity of an air mass. Continental (c) air masses
have relatively low humidity because they originate over land. Maritime (m) air masses have relatively high humidity
because they originate over the ocean or another large body of water. The terms tropical, polar, and arctic define
the temperature characteristics of an air mass. Tropical (T) air masses, because they originate close to the equator,
are relatively warm. Polar (P) air masses are cool because they originate near one of Earth’s Poles. In the winter when
an especially cold air mass that originated in the Arctic enters the United States from Canada, meteorologists call this
an arctic air mass.
Why do tropical and polar air masses have different temperatures?