Download Air Masses, Global Winds and Fronts Guided Notes

Air Masses, Global Winds and Fronts
Meteorology, Weather, and Climate
is the study of atmospheric phenomena. Meteorology includes weather and climate.
•
•
is the short-term variations in atmospheric phenomena that interact and interfere with
the environment and life.
is the long-term variations of weather in a certain area.
Air Masses
An
is a large volume of air that has the same characteristics, such as humidity and
temperature, as its source region.
A
is the area over which an air mass forms.
Source Regions
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Global Wind Systems
The directions of Earth’s winds are influenced by Earth’s rotation.
This
straight line.
results in fluids and objects moving in an apparent curved path rather than a
The directions of Earth’s wind systems, such as the
with the latitudes in which they occur.
and the
, vary
Polar Easterlies
The polar easterlies are the wind zones between
and the south pole.
and the north pole, and
Prevailing Westerlies
The prevailing westerlies are the wind systems on Earth located between latitudes
.
, and
Trade Winds
Between latitudes
are two circulation belts of wind known as the trade winds.
Near latitudes 30 N and 30 S, the sinking air associated with the trade winds creates an area of
. This results in a belt of weak surface winds called the horse latitudes.
Trade winds from the North and the South meet and join near the equator. The air is forced upward, which creates an
area of
pressure.
This process, called
, can occur on a small or large scale. Near the equator, it occurs over a
large area called the intertropical convergence zone (ITCZ).
Jet Streams
A jet stream is a narrow band of
,
,
wind.
in the middle latitudes is strongly influenced by fast-moving, high-altitude jet streams.
Types of Jet Streams
The major jet streams, called the polar jet streams, separate the
westerlies.
from the prevailing
The minor jet streams are the subtropical jet streams. They occur where the
prevailing westerlies.
meet the
Fronts
There are four types of fronts:
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Cold Fronts
Cold Fronts occur when
steep slope. This collision results in
air displaces
air forcing it up along a
.
Warm Fronts
Warm fronts occur when advancing
boundary slope. Often causes widespread
air displaces
air developing a gradual
.
Stationary Front
Stationary Fronts occur when two air masses meet but
.
advances resulting in light
Occluded Front
Occluded fronts occur when a
forcing the warm air
common along an occluded front.
air mass moves so rapidly that it overtakes a
.
front
are
Label the fronts in the diagram below.
Pressure Systems
In the northern hemisphere, winds move counterclockwise around a
a
-pressure center.
-pressure center, and clockwise around