Download warm air

All the Earth’s energy comes from the
sun however…
 The amount of solar energy that reaches
the Earth’s surface varies.
 3 factors affect the distribution of energy
to the Earth:

› Earth’s curved surface
› It’s tilt
› It’s orbit
Because the Earth is round, solar energy
hits the Earth at different angles.
 The concentration of the light that
warms the Earth’s surface is unequal.

Earth’s tilt causes the changing seasons.
 Summer – Northern hemisphere(N.H.) is
tilted towards the Sun. Solar energy hits
more directly causing warmer
temperatures.
 Winter – N.H. is tilted away from the Sun.
Solar energy hits less directly resulting in
colder temperatures.

Changes over a period of 100,000 years.
 From circular  oval  circular again.
 Oval – more solar energy when its near
the Sun and less when it’s further away.
 Circular – solar energy is balanced.

Air above warm areas can be heated
by conduction.
 Air Mass – large mass of air that has
almost identical properties.
(temperature, humidity, and pressure.)
 Often tropic or polar regions.

High Pressure system: region where air is
descending and putting more pressure
on the region below.
How it forms:
 An air mass cools Air becomes more
dense air sinks
 Weather: becomes warmer and drier
resulting in clear skies.

Low pressure system: region where rising
air is leaving less dense air behind. Less
dense air means less pressure.
 When an air mass warms  Air becomes
less dense  causing it to rise.
 Weather: As air rises it cools, condenses
and brings precipitation (WET WEATHER).

Because the Earth is
rotating, any object that
moves on the surface will
also turn:
 to the right (clockwise) in
the N.H. (Northern
Hemisphere)
 to the left
(counterclockwise) in the
S.H.

Jet Stream
Wind happens when high pressure air
moves towards areas of low pressure.
 A Jet stream is a narrow band of fast
moving wind shaped by the coriolis effect
and temperature changes.

Jet streams are
the strongest type
of wind on Earth
(300 km/h and up)!
 Storms and big
Weather systems
usually form and
travel on the jet
stream.

FRONT
Where two different air masses
meet and do not mix.
2 Types of weather
fronts:
Cold Front
Warm Front
Cold Front
When a fast moving cold air mass slides under a
slow moving warm air mass and pushes it up.
Cold Fronts bring:
Intense but short-lived precipitation
 Thunderstorms (sometimes Tornadoes!!)

A cold front symbol—The
direction of the teeth show
the direction the front is
moving.
Warm Front
When a moving warm air mass moves over top
with a slowly moving cold air mass.
Warm Fronts bring:

Warm weather and clear skies
Warm Front symbol—The
directions that the bumps
face is the direction the
front is moving.