Download Atmosphere

Atmosphere - layer of gases that surrounds a
planet or moon held by gravity
(ocean of air)
Composition
• Atmosphere is a
Mixture of
– Gases
– Dust
– Water vapor
• clouds and
precipitation (rain)
• Absorbs heat and
energy from the sun
• changes by time
and place
Ozone (O3) – very rare and less stable type
of oxygen molecule that combines 3 atoms
of oxygen
• Thin layer is found in
the Stratosphere
– 3 ozone for every
10,000,000 air
molecules
• Protects living things
from harmful UV sun
rays
• Manmade chemicals
destroy ozone. Humans
have thinned the layer
above the Antarctic
Carbon Dioxide (CO2) - naturally occurring gas in our
atmosphere
• Needed for
photosynthesis to
occur during the
Carbon Cycle
• (photosynthesis) plants take in (CO2),
solar energy, and
water and produce
carbohydrate
energy (sugars) and
Oxygen
Water Vapor - water in the atmosphere
• Key to understanding atmosphere processes
• Water vapor is the source of all precipitation
• Examples
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Clouds
Fog
Rain
Snow
Sleet
hail
Changing state of matter
• changing matter
requires energy is
transferred in the
form of heat
• Latent heat – heat
used doesn’t cause
temperature
change
How water changes states of matter in
the atmosphere
• All water passes
through the
atmosphere as
water vapor
• Water changes
from one state
of matter to
another
o Solid to liquid
o Liquid to gas
o Solid to gas
Greenhouse Effect – The warming of Earths surface
and lower atmosphere when carbon dioxide, water vapor and
other gases absorb and reradiate (heat) energy
The atmosphere is divided into 4 main
layers by temperature
• Troposphere (bottom layer)
• Stratosphere (where important weather
occur)
• Mesosphere
• Thermosphere (top layer)
• It generally gets colder as altitude increases
• Layers of the atmosphere are divided by
temperature and height
Layers of the
atmosphere
Weather – the state of the atmosphere
at any given time and place
• Climate – average weather conditions in an
area over a long period of time
Earth-Sun relationship
• Almost all energy that causes Earth’s weather
and climate comes from the sun
• Unequal heating of Earth causes weather
• Heat transfers in 3
ways
1. Conduction – transfer
of heat through
molecular activity
(high to low temp)
2. Convection – transfer
of heat by mass
movement or
circulation within
something
3. Radiation – transfer of
heat in all directions
Heat transfer
Solar radiation – when radiation strikes
an object, 3 things happen
1. Energy is
absorbed by the
object
2. Energy is
transmitted and
doesn’t add to
the object
3. Energy is
reflected or
bounced off the
object
• Reflection – when
light bounces off
an object
Scattering – when a
large number of
weaker rays are
produced traveling
in different direction
Other factors that influence energy
coming into the atmosphere
• Earth’s rotation –
spinning
• Earth’s revolution
– orbit around
sun
• Earth’s
orientation – how
Earth is tilted on
it’s axis in relation
to the sun
Humidity – the amount of water vapor
in the air
• Relative humidity – the
amount of water in the
atmosphere. % of how
much the air can hold
• Saturation – when the
atmosphere has reached it’s
maximum amount of water
vapor it can hold at a
temperature and pressure
Dew point
• The temperature when water vapor in the air
condenses (changes) into a liquid from a gas
Cloud Formation
• As air rises in
the atmosphere
it expands and
cools
• When air
reaches it’s dew
point, clouds
begin to form
Air compression
• When air
pressure
increases, air
temperature
rises
• Motion of
the gas
molecules
increases
• When air
pressure
decreases, air
expands and
temperature
cools
•Motion of
the gas
molecules
slows
Orographic Lifting
• when air is
forced to
rise and cool
due to
terrain
features
such as hills
or
mountains
Frontal Wedging
• When cold dense air acts as a
barrier and causes warmer,
less dense air to rise
Convergence
• When air masses
flow together from
more than 1
direction, air rises.
Low pressure is
the result
Localized convective heating
• Unequal heating of Earth’s surface causes
pockets of air to be warmed more than
surrounding air
• Causes pockets of air to rise, forming thermals
Clouds – 3 basic types are classified on
form and height
Cirrus
Cumulus
Stratus
High Clouds
a) cirrus
b) cirrostratus
c) cirrocumulus
• Thin and white
• Low precipitation
• May warn of
approaching stormy
weather
cirrocumulus
Middle Clouds - alto
altocumulus
a) Altocumulus – large
and dense
b) Altostratus – white
or gray sheet
covering sky
c) Cumulonimbus • Infrequent light
snow or drizzle
Low clouds
a) Stratus – fog like layer
covering sky
- Occasionally produce
light precipitation
b) Stratocumulus – rainy
clouds
c) Nimbostratus – main
precipitation maker
d) Cumulus - clouds with
vertical development
Stratocumulus
Fog – cloud with base at or near the
ground
• Form by
1.Cooling – air
over a cold
surface
2.Evaporation –
when cool air
moves over
warm water
(steaming)
How precipitation forms
• Tiny cloud
droplets
grow in
volume by
about
1,000,000
times.
Cold cloud precipitation
• Ice crystals
contact with
cloud droplets
causing them to
freeze
• Causes ice to
grow into
snowflakes
• Rain often begins
as snow high in
the clouds
Warm cloud
precipitation
• Large droplets
moving
through the
clouds collide
and join
(coalesce) with
smaller
droplets
The type of precipitation that reaches
Earth’s surface depends on
temperature in the lower atmosphere
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Rain
Snow
Sleet
Glaze
Hail
Atmosphere key ideas
1. Earth’s atmosphere is made up of a combination of gases.
The major components of nitrogen, oxygen, and argon remain constant over time and space,
while trace components like CO2 and water vapor vary considerably over both space and
time.
2. The atmosphere is divided into the thermosphere,
mesosphere, stratosphere and troposphere
3. boundaries between these layers are defined by changes in
temperature and height
4. Pressure decreases exponentially with altitude in the atmosphere.
5. Our knowledge about the atmosphere has developed based on data from a variety of
sources, including direct measurements from balloons and aircraft as well as remote
measurements from satellites.