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Concept Sheet
Atmosphere and Weather
6.3: The student will investigate and understand the role of solar energy in driving most natural processes within
the atmosphere, the hydrosphere and on the Earth’s surface.
1. The Earth’s surface is heated by the radiation from the Sun. Only about half of the Sun’s energy reaches the
Earth. Once the Sun’s energy enters the
atmosphere it can be absorbed, reflected or
scattered by clouds, the ground, water, dust
and water vapor. About 4% of the energy is
reflected back into space right away. Some
energy is reflected several times, which leads
to some being absorbed.
The solar energy that makes it to Earth
powers the convection currents in our
atmosphere and oceans, as well as all the
photosynthesis on Earth.
2. The Earth’s energy budget is a system. The
solar energy coming in is the input, and the
energy escaping out is the output. Like all systems, it needs to be kept in close balanced to function
properly. If too much energy goes out, the climate on Earth will cool down. If too much energy is kept, the
climate on Earth will heat up. Even a small change to the overall climate of Earth can drastically impact the
amount and type of life that is able to survive on Earth.
The Earth’s atmosphere can be compared to a greenhouse. The glass in a
greenhouse, like our atmosphere, allows the solar radiation in and helps
trap the thermal energy in. This keeps the environment in the greenhouse
warm. The process of our atmosphere trapping thermal energy is called
the Greenhouse effect.
The greenhouse effect is responsible for keeping all life on Earth within
livable temperature ranges. There are three main greenhouse gases:
water vapor, carbon dioxide (CO2), and methane (CO4). These are all
naturally produced, however human activity such as burning of fossil
fuels, cutting down and burning of forests, and large scale cattle
production increases the amount of these greenhouse gases in our atmosphere. These activities also reduce
the number of plants who would take the CO2 out of the atmosphere and use it to make food.
If the amount of greenhouse gases continues to rise, the atmosphere will heat up and Earth’s climate will
change, often called Global Warming. Polar ice caps could melt and sea levels rise, which would cause
coastal flooding. Wide spread drought could also occur, making it difficult for some areas to grow crops. An
increased number of hurricanes could also occur due to warmer bodies of water.
3. Convection is the movement of heat in a fluid (liquid or gas).
A Convection current occurs when part of a fluid is heated, which causes the molecules to move faster and
move further apart. They become less dense and rise up. As they rise further way from the heat source, they
cool and condense, becoming less dense and causing them to sink down. As they near the heat source, they
heat up again and the cycle of heating and cooling begins again. Convection currents in the ocean cause
currents, in Earth’s mantle they are responsible for tectonic drift, and in our atmosphere they create wind.
Land and water do not absorb solar radiation evenly. Water takes a much longer time to change temperature,
while land heats up and cools down rapidly. This uneven heating creates
winds, as well as land and sea breezes. It also causes areas near large
bodies of water to have less temperature variation through the seasons.
4. All the conditions in the atmosphere at a given time is called weather.
Weather is influenced by temperature, humidity, and air pressure
Daily temperatures, or amount of heat in the air, are influenced by the
conditions, such as cloud cover, winds, season, time of day, and the
amount of water/land nearby. It is measured with a thermometer.
Humidity is the amount of water vapor in the air. Remember, water
vapor is invisible – if you can see it, its water or ice, not water vapor. Humidity is often discussed in
percentages as relative humidity, which shows the percent of water vapor in the air compared to what the
air could hold. Warm air can hold more water vapor than cold air, which is why in the summer a day with
70% humidity feels more humid than a winter day with 70% humidity. One tool we use to measure
humidity is a hygrometer.
Air pressure is the force exerted by the weight of the air in
the atmosphere on objects below. If you were to have a
barometer with you and wanted to measure air pressure at sea
level and as you climbed a mountain. You would notice that
air pressure drops as you move up in our atmosphere.
5. Climate often gets confused with weather. What we
experience in the short term (hours, days) is weather, the
average pattern of the day to day weather over a long period of
time (months, years, decades).
6.6: The student will investigate and understand the properties of air and the structure and dynamics of the
Earth’s atmosphere.
6. Air is a mixture of gaseous elements and compounds. The four main
gases that make up our atmosphere are (from most prevalent to least):
Nitrogen (78%), Oxygen (21%), Argon (0.9%),
Carbon Dioxide and others (less than 1%)
7. The atmosphere is made up of layers with distinct characteristics. There
are four (4) main layers: Troposphere, Stratosphere, Mesosphere and
Thermosphere. About 80% of all the air in our atmosphere and nearly all of the weather is in the
Troposphere
The Mesosphere has
lower air pressure
(air is less dense)
than the
stratosphere.
Temperature also
decreases in this
layer. Meteors burn
up in this layer.
The Troposphere is the
lowest layer. It is where
we live and where
weather happens. It
has the highest density
of air molecules, so also
the highest air
pressure. As you rise up
in altitude the
temperature decreases.
The Thermosphere is not very dense with
air molecules, but it is also the hottest
layer, temps as high as 1700C. Where it
ends is difficult to tell, but most people
agree it extends from about 85km to
320km above the ground. Space shuttles
orbit in this layer.
The Stratosphere contains the ozone
layer, which is very important in
protecting up from harmful solar
radiation. The temperatures increases
with altitude. Large jet planes often fly in
the lower stratosphere because the air is
more stable (no weather) so it’s a
smoother ride.
Memory Trick:
For the layer order:
Timmy Says Merry Thanksgiving
Natural events, such as forests fires and volcanic eruptions, affect our atmosphere and climate because they put
gases and particles into the atmosphere and upset the Earth’s energy budget. Human activities, like pollution
also contributes. We are still learning about how our activities affect our atmosphere. Our ozone layer is
composed of O3 compounds instead of O2. Ozone in our troposphere is toxic, but in our stratosphere it acts as a
natural sunscreen. CFCs (chlorofluorocarbons) used in aerosol sprays, as solvents, and as refrigerants built up in
the stratosphere and created holes in the ozone layer exposing us to harmful UV radiation. Since banning the
extensive used of CFCs, the ozone has begun to slowly heal itself, something scientists were unsure if it would
be able to do.
Every person’s influence on the air affects everyone. That is why maintaining good air quality is everyone’s
responsibility and an important goal for modern society. People, local governments and federal
governments are all active participants in protecting the environment through their actions and creation of laws.
8. Weather conditions are determined by the thermal energy, water vapor and pressure of the air across a large
region. A large area of air that has similar properties is called an air mass. A cold air mass is called a polar
air mass, while a warm air mass is called a tropical air mass. An air mass with high levels of water vapor,
generally coming from an ocean, is called a maritime air mass; while dry air masses are called continental
air masses. When two different air masses meet, such as a polar continental air mass and a tropical maritime
air mass, a boundary called a front is formed. Fronts hold important clues to how weather will change.
Meteorologists (weather scientists) create weather maps based on pictures of fronts and storms from pictures
taken by
Common National Weather Service Symbols
satellite.
Weather maps
Weather
Symbol
Weather
Symbol
Weather
Symbol
Weather
Symbol
are important
Drizzle
Rain
Smoke
Cold front*
for
Fog
Shower
Thunderstorm
Warm front*
understanding
Hail
Sleet
High pressure
Stationary front*
and predicting
*
Triangles
or
half-circles
on
a
front
symbol
point
in the direction
Hurricane
Snow
Low pressure
Occluded
front* a front is moving
the weather.
9. There are four (4) main cloud types
in various levels of the troposphere.
The cloud types often indicated the
weather conditions in the areas.
Cloud Type
Cirrus
Cumulus
Altitude
Very high
(over 6,000 m)
Medium
(sometimes low)
Stratus
Low
Cumulonimbus
From low to high
Characteristics
Thin, wispy, feather-like.
Made of ice crystals.
Flat on bottom with puffy
tops (like cotton balls)
Flat, gray layers across the
sky.
Big, towering clouds that
are flat on the bottom.
Condition
Good weather, but a change on the
way.
Good weather
Overcast days, sometime with light
constant drizzle or snow
Storms (thunder storms, sometimes
tornadoes/hurricanes)