Download Layers of the Atmosphere

Section 13.4
The Atmosphere
On top of the world

Summit
On top of the world Version 2.0
Felix Baumgartner
Properties of the Atmosphere

Blanket of air and moisture that
surrounds the earth.

Extends about 500km above the earth.

Most dense at sea level. Density
decreases as elevation increases.
(Particles become further apart)
Layers of the Atmosphere
Layers of the Atmosphere
 The
atmospheric layers differ in:
 altitude
(height above sea level)
 Temperature
 Composition
 pressure
Layers of the Atmosphere
 Atmospheric
layers are
thicker above the equator
than at the poles
 Warm
air expands and cool
air contracts
 It is warmer at the equator
so it takes up more
volume.
Layers of the Atmosphere

Use your text pages 510-511 and
Figure 3 to add details to the
Atmosphere Layers handout.
Troposphere

.
9
Stratosphere
10
Mesosphere
11
Thermosphere
12
Thermosphere
13
Exosphere
14
How does the Atmosphere support
life?
How does the Atmosphere support life?
1. Provides oxygen and nitrogen required for basic life functions
How does the Atmosphere support life?
2. Has carbon dioxide needed by plants in photosynthesis
How does the Atmosphere support life?
3. Protects the earth from harmful radiation
How does the Atmosphere support life?
4. Regulates temperature by trapping heat and moving it from one
place to another.

http://earth.nullschool.net/
How does the Atmosphere support life?
5. Involved in the water cycle, and all organisms need water.
How does the Atmosphere support life?
6. Burns up asteroids preventing many dangerous collisions.
Atmospheric Pressure
 The
force the air
exerts on objects
as gravity pulls it
towards the center
of the earth
 Greatest
at sea
level since the
height, and
therefore weight,
of the atmosphere
is greatest.
Atmospheric Pressure
 As
altitude
increases (climbing
mountain) the
weight of the air
above is less and
pressure is less.
Atmospheric Pressure

Another factor that
affects atmospheric
pressure is whether the
air is rising or falling.
Rising air has less pressure
than falling air.
Measuring Pressure (Units)

Atmospheric pressure (also called barometric pressure) is measured
with a barometer.

Pressure is most often measured in Kilopascals (kPa)
Kilo = 1000

1KPa = 1000 pascals (Pa)
100 KPa = 100 000 Pa
You may also hear of pressure in Atmospheres (atm) or
millibars (mb)
Measuring Pressure (Units)
Samples:
1) Convert 54 kPa to Pa.
2) 757840 pascals to kilopascals
Answers
1) 54000 Pa
2) 757.840 kPa
Measuring Pressure (Units)


Standard Atmospheric Pressure is the normal atmospheric pressure
at sea-level. It is assigned a value of 101.3kPa.

Low Pressure systems have a pressure less than 101.3 kPa

High pressure systems have a pressure above 101.3 kPa
We will learn shortly how air pressure actually affects weather. It is
very important.
Pressure Gradient

A measure of how the atmospheric pressure
changes across the earth's surface

This change can be either vertical or
horizontal.


Vertical is like how it changes with altitude.
Horizontal pressure gradients can be shown on a map by joining points of
equal atmospheric pressure.

They can then be used to predict where high and low pressure areas are
and the direction and strength of winds.

Wind moves from high pressure to low pressure.
C
B
A
Temperature Gradient

Clouds