Intro to Meteorology: Our Atmosphere

(Not on Notes Page…)
Meteorology – the study of atmospheric phenomena
(weather and climate).
•“Meteor” is derived from ancient Greek meaning “high in
the air.”
•Clouds, raindrops, dust, fog, and rainbows are atmospheric
“meteors.”

Weather – the current state of the
atmosphere.
What is the weather in our area?
Climate – the long term average state
Q: What is the climate in Hawaii? Alaska?

Earth’s Atmosphere

This is an image of the sunrise from space over the South China Sea.
An astronaut would see something like this; clearly defined bands of
color through the atmosphere as the sun rises. The brightness of the
colors in the atmosphere in this photograph is due to the amount of
dust in the atmosphere.

Development of the Atmosphere
Early Atmosphere
• During the 1st billion years of Earth’s formation, there was a
lot of volcanic activity (Outgassing).
•Released water vapor (H2O), chlorine (Cl), carbon dioxide
(CO2), hydrogen (H), and nitrogen (N).

•The Past Atmosphere:
Billions of years ago the
Earth’s atmosphere
contained two deadly gases:
Ammonia (NH3) and
Methane (CH4).
•NO OXYGEN YET!

•After several million years, the planet cooled,
water vapor condensed and absorbed most of the
carbon dioxide.

•Storm clouds formed that produced heavy rains
which formed the first oceans.

•It is believed that some of Earth’s water may
have originated from numerous collisions with
small collisions with small meteors and
disintegrating comets* when the Earth was
young.
*carbon dioxide, methane and water with dust and various mineral aggregates

How did the atmosphere become
safe for us?
1) Oxygen was formed from the
dissociation of water molecules and
by photosynthesis of primitive
bacteria called cyanobacteria. This
blue-green bacteria appeared 3.5
billion years ago and triggered the
release oxygen as a waste product on
earth.

Where did the oxygen come from cont…
2) By a slow increase in concentration as rays from the
sun split water vapor (H20) into hydrogen and oxygen.

•Hydrogen (H) drifted off to space, while Oxygen (O) remained
in the atmosphere.
3) Plants also contributed to the formation of oxygen
(photosynthesis: the process of using energy in sunlight to
convert water and carbon dioxide into carbohydrates (sugars)
and oxygen.

Intro to Meteorology: Our Atmosphere

This image shows the average temperature profile through the
Earth's atmosphere.

Layers of the Atmosphere:
The atmosphere surrounds Earth and
protects us by blocking out
dangerous rays from the sun. The
atmosphere is a mixture of gases that
becomes thinner until it gradually
reaches space. It is composed of
Nitrogen (78%), Oxygen (21%),
and other gases (1%). Also, it
contains dust and salt, which is
important for the formation of
clouds.

The atmosphere is divided
into five layers. It is thickest
near the surface and thins out
with height until it eventually
merges with space.

1. The Troposphere
•The lowest layer of the Earth's atmosphere.
•Temperature decreases as height increases (3.6
degrees/1000 ft).
•Most dense (due to compaction of molecules).
•Around the equator, the height is about 16 km.
•air is slightly unstable.
•ALL WEATHER occurs in the Earth's
troposphere!!!
•0 – 11 miles up.

This is an image of the clouds in the Earth's troposphere.

2. The Stratosphere
•Altitude of 50 km. (11 miles to 30 miles).
•On Earth, ozone causes the increasing
temperature in the stratosphere. Ozone is
concentrated around an altitude of 25
kilometers. The ozone molecules absorb
dangerous kinds of sunlight, which heats
the air around them.
Many jet aircrafts fly in the stratosphere
because it is very stable.

If ozone is decreased, it can
cause:
 Skin cancer
 Eye cataracts
 Sun burning
 Suppression of the human immune
system.
 Adverse impact on crops and animals due
to the increase of UV radiation
 A reduction of ocean phytoplankton.

Polar stratospheric clouds, also known as

3. The Mesosphere
•Temperature decreases with altitude. (30 – 55 miles)
•The atmosphere reaches its coldest temperature of
around -100°C in the mesosphere.
•Air pressure decreases.
•Does not have a lot of oxygen (at this level our
brain would be oxygen-starved called hypoxia.
•This is also the layer in which a lot of meteors burn
up while entering the Earth's atmosphere.

4. The Thermosphere
• 55 – 80 miles up.
The “warm layer.” This is due to the O
molecules absorbing solar rays, heating the air.
• When the sun is active, the thermosphere can
heat up to 2,000°C or higher!
• includes the region of the atmosphere called
the ionosphere. The ionosphere is a region of
the atmosphere that is filled with charged
particles (ions).

• Important for radio communication.

The space shuttle orbits in the
thermosphere of the earth.

5. The Exosphere
•Very high up, the Earth's atmosphere
becomes very thin. The region where
atoms and molecules escape into space is
referred to as the exosphere.
•The exosphere is upper part of the
thermosphere.
•Extends about 550 km above the
surface. (80 miles and up!)
•Satellites orbit in the exosphere.

This is a picture which shows the Earth, its atmosphere (the
clouds are likely in the troposphere and stratosphere), the limb of
the Earth (the dark blue curve/edge which is the mesosphere and
thermosphere), and the dark blue to black region of space (where
our exosphere extends out to...).

•It is made up of positively charged
protons and negatively charged
electrons. The Earth is a large magnet.

•Van Allen radiation belts: the charged particles that are
concentrated into belts, or layers of high radiation.
•When there is a solar flare, it is bombarded with electrically
charges particles. Aurora borealis or northern lights.

Comet Hale-Bopp in the 29 March 1997

Solar Fundamentals (Energy transfer) 3 ways:
Why Learn? Uneven heating of the Earth causes weather!
1) Radiation – transfer of energy through space by visible
light, electromagnetic waves, and ultraviolet waves. Earth
absorbs and reflects this energy. Sunlight is a form of
radiation that is radiated through space to our planet without
the aid of fluids or solids.

2) Convection – transfer of energy due to heat flow.
• Hot air rises, cold air sinks (density)!
• Affects weather.
*Hot substances are less dense than cold substances.
*Cool substances are more dense than hot substances.
EX. Mantle convection, wind, and wind drafts.

3) Conduction - is the process by which heat energy is
transmitted through contact with neighboring molecules
(substances – solids, liquids, and gas).
• Some solids, such as metals, are good conductors of heat
while others, such as wood, are poor conductors. Air and
water are relatively poor conductors.
• Since air is a poor conductor, most energy transfer by
conduction occurs right at the earth's surface. At night, the
ground cools and the cold ground conducts heat away from
the adjacent air.

•Heat ALWAYS
travels from warmer
areas to cooler areas.
•Examples?

How does this relate to our weather?
Let’s tie it all together:
radiation, convection, and conduction.

•During the day, solar radiation heats the ground, which heats the air
next to it by conduction, which can form convection currents.

1. Construct a concept map that describes the processes of the
water cycle:
Water cycle
• Evaporation
• Condensation
• Precipitation
• Water changes from liquid to gas
• Water changes from gas to liquid
• Water falls as rain, snow, sleet, or hail
2. Construct a concept map using these terms :
Conduction, radiation, convection, energy transfer
Transfers energy by electromagnetic waves, occurs when molecules
collide, occurs through the flow of a heated substance

11.2 State of the Atmosphere.
1) What is the difference between heat and temperature?
2) What is the difference between Fahrenheit, Kelvin, and
Celsius? What temperature does water boil for each unit?
What temperature does water freeze for each type of unit?
3) Define dew point and condensation.
4) What is lifted condensation level?
5) What happens to the density of air as you decrease in
elevation? Why?
6) Describe the Temperature- Density - Pressure
Relationship.
7) Describe why wind “blows.”
8) What is humidity? Relative humidity? How does this

Intro to Meteorology: Our Atmosphere

Related slideshows

More Related Content

Intro to Meteorology: Our Atmosphere