Transcript Atmosphere Power Point

Atmosphere
The surrounding air of the Earth
Layers of the atmosphere
• There are 4 layers in
the atmosphere
• They are the
troposphere,
mesosphere,
thermosphere, and
stratosphere
Troposphere
• This is the layer that
is closest to the
surface of the earth
• It’s elevation ranges
from 0 to 10 km
Stratosphere
• This 2nd layer sits on
top of the troposphere
• It’s elevation ranges
from 10 km to around
25 km
• This layer contains
the ozone layer,
which protects us
from harmful sunlight
Mesosphere
• This 3rd layer is above
the stratosphere
• It’s elevation ranges
from 25 to 100 km
Thermosphere
• This is the highest layer
of the atmosphere
• It’s height ranges from
100 to 400 km
• This is where most small
meteorites burn up and is
also the location in the
atmosphere that the
northern lights occur
(aurora borealis)
Composition of Air
• There are many
different types of
gasses in the
atmosphere
• They include nitrogen,
oxygen, argon,
carbon dioxide and
other noble gasses
• The gas that is most
abundant is nitrogen
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Air Pressure
• The measure of the force that the air
molecules push on a surface
• Air pressure “pushes” an object in all
directions
• As altitude increase, air pressure
decreases
Altitude
• The height of an object above Earth’s
surface
• The greater the altitude, the less amount
of air pressure
Ozone
• Located in the stratosphere, is a molecule
made up of 3 oxygen atoms that absorb
solar energy in the form of ultra-violet (UV)
radiation warming the surrounding air
• Radiation- the transfer of energy through
empty space
– Energy from the Sun heating the Earth’s
surface
– Takes place when there is NO direct contact
between surfaces
• Conduction- heat transfer by direct contact
of particles of matter
– Example: a metal spoon sitting in a hot bowl
of soup
– Heat will ALWAYS travel from the warmest
object to the coolest object!
• Convection- heat transfer involving the
movement of fluids-liquids & gases from
one particle to another
• Caused by different temperatures &
densities within the fluid
• Heat rises & cold sinks
• Greenhouse effect- a heating process on
Earth where the gases in the atmosphere
(ozone layer) trap thermal energy keeping
the troposphere at a livable temperature.
– 50% of the radiation that enters the Earth’s
atmosphere is absorbed by the Earth’s
surface
• Global warming- the gradual warming up
of Earth’s atmosphere
– Contributes to the depletion of the ozone layer
– Caused by human activity mostly
• Burning of fossil fuels, deforestation, CFC’s, ect.
• Wind- A flow or current of directionally
moving air
– Due to the Earth’s counterclockwise
rotation, the Northern Hemispheres wind
patterns typically blow from the west to
the east
– Can be either a warm or cold wind
pattern
– Ocean current mimic wind patterns
• Coriolis Effect- The curved path that the
rotation of the Earth causes the wind to
travel in
– Winds in the Northern Hemisphere travel to
the right & in the Southern Hemisphere they
travel to the left
• Trade winds- Winds that blow from 30 degrees latitude
to the equator
– They are in both hemispheres
– Have been used by sailors for hundreds of years
– Doldrums
• Where the northern & southern hemisphere trade
winds meet in an area of low pressure
• Very little wind; means “foolish” in Latin
– Horse Latitudes
• Area of weak winds at 30 degrees north & 30
degrees south latitude
• Legend states that sailors would throw horses over
the sides of their boats to make the boat lighter to
sail
• Westerlies- wind belts found in both the
Northern & the Southern hemispheres
between 30 degrees and 60 degrees
latitude
– Flow toward the poles in the opposite
direction of the trade winds
– Helped early traders return to Europe
• Polar easterlies- wind belts that extend
from the poles to 60 degrees latitude in
both hemispheres; Form from cold sinking
air
• Jet streams- narrow belt of high-speed
winds that blow in the upper troposphere
and lower stratosphere; do NOT follow a
regular path around Earth
– changes speeds often and can exceed 500
km/hr
– Wind that blows the weather systems across
the land