Download Air Masses notes 2017

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Name______________________________________Date______________Period_______________
An air mass is a huge body of air that has similar temperatures, humidity (measure of the amount of
water vapor in the air), and air pressure at any given height.
The characteristics of air masses depend on the temperatures and moisture content of the area over which the air
masses form.
Temperature

Tropical, or warm, air masses form in the tropics (near the equator) and have low air pressure.

Polar, or cold, air masses form north of 50 degree north latitude and south of 50 degree south latitude.
These have high air pressure.
Moisture content

Maritime air masses form over oceans. Water evaporates from oceans, so the air becomes very humid.

Continental air masses form over land and have less exposure to large amounts of moisture from
bodies of water. Therefore, these air masses are dry.
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Maritime, Polar
Maritime, Polar
Continental, Polar
Maritime, Polar
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Maritime, Tropical
Continental, Tropical
Maritime, Tropical
Maritime, Tropical
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Air Masses Over North America
Directions: Answer the following short answer questions below.
1.
Analyze the characteristics of the following air masses (based on their humidity/moisture and
temperature):
a. Maritime tropical: humid & warm with low pressure forming over ocean
b. Continental Tropical: dry & warm with low air pressure forming over land
c. Maritime polar: humid & cold with high pressure forming over ocean
d. Continental polar: dry & cold with high pressure forming over land
2.
Describe how air masses are classified (HINT: Based on two categories) Temp &
Moisture/Humidity
3.
Compare and Contrast a continental tropical air mass to a continental polar air mass.
Continental Tropical
Continental Polar
-cold
-warm
-low pressure
-forms near the
equator
BOTH
-dry
-forms
over
land
-high pressure
-forms above 50
degree N latitude
& below 50
degree S latitude
4. Application: How do air masses that form over the land and ocean affect weather in the United
States?
Air masses that form over land will bring little or no precipitation.
Air masses that form over oceans will bring lots of precipitation (rain or snow).
5. Identify and explain the source of energy that moves air masses around the earth.
The Sun is the source of energy that moves air masses around the earth because it
heats land and water at different rates (unequal heating). This movement of air of
different temperature, density, and pressure results in the formation of wind.