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Atmosphere notes
Earth’s Atmosphere- The atmosphere is made up of gases- 78% Nitrogen, 21% Oxygen,
1% other trace gases including Carbon Dioxide
- The atmosphere protects us from Sun’s harmful rays and helps to
maintain a regulated temperature
- The atmosphere is made up of different layerso Troposphere- layer in which we reside, this layer contains
about 99% of the water vapor in the atmosphere and 75% of
the gases; also where clouds and weather occur
o Stratosphere - this layer contains the Ozone layer (which
deflects much of the UV rays from the Sun
o Mesosphere – this is the third layer from Earth
o Thermosphere – this layer burns up matter that comes
toward Earth (meteors); also the thickest layer
o Exosphere – last layer; very thin air; boundary to space
Atmospheric Pressure- Pressure is the highest closest to Earth; the higher
the elevation the lower the pressure becomes
Energy Transfer- Energy from the Sun is transferred to Earth by radiation.
Radiation is energy transferred in the form of rays or waves.
Upon getting this radiation, the heat is then moved in the atmosphere by
conduction and convection.
Conduction- energy that is transferred by the bumping of molecules
together
Convection- transfer of energy by flow of material
All three of these are needed to keep the atmosphere heated.
Air Movement-
The uneven heating of Earth’s surface creates different temperature air.
When the warmer and cooler air mix, wind is formed.
Coriolis effect- this causes air and water to turn toward the Equator due
to Earth’s rotation.
Jet Stream- narrow belt of strong winds that blows near the top of the
troposphere- stronger in the winter due to greater difference in
temperature- moves from west to east
Weather- state of the atmosphere at a specific place and time; factors that
determine weather are: air pressure, humidity, temperature and wind
Humidity vs. Relative humidityHumidity is the amount of water vapor in the air
Relative humidity is the measure of the amount of water vapor in the air
that a certain temperature can hold- ranges from 0 to 100 (given in
percents)
Clouds are formed as warm air moves upward, expands, and cools. Made
up of water vapor, dust and salt.
Clouds are classified by their shape and height.
Weather patterns
Air masses- large body of air that has properties similar to the part of
Earth that it is over- there are 6 masses that help to form our weather in
the U.S.
Low pressure systems- called cyclones and are associated with stormy
weather
High pressure systems- called anti-cyclones and are associated with fair
weather
Fronts- the boundary between two air masses of different properties. All
fronts bring some form of precipitation.
There are four frontsCold front- blue line with triangles, occurs when colder air moves toward
warm air- this lifts the warm air, cools and condenses to form clouds- if
there is a large temperature difference then a thunderstorm will occur
Warm front- red lines with semicircles, form when lighter, warmer air
advances over heavier, colder air.
Stationary front- shown as alternating red and blue lines with both
semicircles and triangles, occurs when two air masses meet up and stop
advancing. Will last for many days and can produce light precipitation
Occluded front – shown by a purple line with semicircles and triangles,
occurs when three air masses meet up (cold, cool, and warm), the warm
air is forced upward
Severe weather
Thunderstorms- occurs in warm, moist air masses and along fronts;
produce a cumulonimbus cloud
Tornado- violent, whirling windstorm that crosses land in a narrow path
and can result from wind shears inside a thunderhead
Hurricane- large, severe storm that forms over tropical oceans, has winds
of at least 120 km/h, and loses power when it reaches land
Watch- means that conditions are right or favorable for severe weather
Warning- means that severe weather conditions exist and you should take
cover right away
Remember to look over the symbols to make sure you understand them.
Page 163 in the book can help as well.
Climate – pattern of weather that occurs in an area over many years;
determines what plants and animals can survive and the way we live
Factors that determine climate: latitude, large bodies of water, ocean
currents, mountains (rainshadow effect), and cities
Climatic changes
Seasonal changes- the position and tilt of the Earth to the Sun creates
different seasons
High latitudes- determine the amount of radiation from the sun that
parts of Earth receive affecting the climate of the area
El Nino- climatic event that begins in the tropical Pacific Ocean; ocean
temperatures increase; may occur when trade winds weaken or reverse,
can disrupt normal temperature and precipitation patterns around the
world
La Nina- opposite of El Nino; stronger winds, instead of weaker ones
Climate change- term used by scientists to describe changes to the
Earth’s weather and climate as a result of different factors. These factors
could be natural or human basedGreenhouse gases- gases in the atmosphere that trap heat energy and
support life on Earth
Greenhouse effect- process by whish heat is trapped in the atmosphere
by gases that hold the sun’s heat. Heat is trapped in the atmosphere by
gases that form a blanket arounf the Earth.
Many of the climatic changes that occur are of a natural cycle that Earth
is going through. Scientists take samples from glaciers to determine the
trends.
Humans are creating an impact on the cycle. Increased carbon dioxide
and deforestation are helping to change the climate in other ways.