The Restless Atmosphere

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The Restless Atmosphere

• Weather

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The Atmosphere

• The atmosphere is a blanket of gases surrounding
  the earth.
• It is made up of a mixture of different gases.

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The Earths Atmosphere
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The Earths Atmosphere
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Solar Energy Energy from the Sun

• The sun provides us with heat and light.
• However, not all of the suns energy reaches our
  planet.
• 50 of the suns energy reaches planet earth.
• 25 is deflected back into space by dust and
  clouds in the atmosphere.
• 25 is absorbed as it passes through the
  atmosphere.

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Latitude

• Latitude means distance North or South of the
  equator.
• It is measured in degrees.
• In general, the further a place is away from the
  equator, the colder it will be.
• There are 3 reasons for this.

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Latitude

• 1. We know the suns energy is absorbed as it
  passes through the atmosphere. Well, at the poles
  the atmosphere is thicker than at the equator.
  Therefore, less heat gets through to the polar
  regions.
• 2. At the equator the sun shines directly
  overhead. This means the heat is concentrated on
  a small area and so this area becomes hot.
• 3. At the poles the suns energy is slanted and
  it is spread over the curved surface of the
  earth. This means it has to heat up a larger area
  and so this area does not heat up as much.
• In summary, less heat gets through to the poles.
  It has to heat up a large area.
• Lots of heat gets through to the equator. It has
  to heat up a smaller area.

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How Latitude influences Temperature
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Wind

• Wind is moving air.
• Air moves from High pressure areas to Low
  Pressure areas.

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Winds and Air Pressure

• Air moves from High Pressure areas to Low
  Pressure areas.
• Some places on the earth have high pressure and
  some have low pressure. But why?
• Warm air rises leaving areas of low pressure.
• Cold air descends creating areas of high pressure.

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High Pressure and Low Pressure
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Winds and Air Pressure
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High and Low Pressure Areas

• If we apply this principle to the earth we see
  that some places on the earths surface will have
  high pressure and other areas will have low
  pressure.
• These areas of different pressure create wind.

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Global Wind Patterns
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Global Wind Patterns

• We now know that winds travel from HP areas to LP
  areas.
• This creates a regular pattern of the different
  winds on the earth.

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Global Winds and the Coriolis Effect

• The earth is spinning on its axis.
• Because of this the winds are deflected at an
  angle.
• They are deflected to the right in the Northern
  hemisphere, and to the left in the southern
  hemisphere.
• This is called the Coriolis Effect.

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Ocean Currents
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Air Masses

• An air mass is a body of air with its own
  temperature, pressure, and humidity level.
• Air masses can effect the weather of the
  countries they pass over.
• Many different air masses meet over Ireland so
  our weather changes a lot.
• There are 4 different air masses which effect
  Irelands weather.
• 1. Polar Air Masses
• 2. Continental Air Masses
• 3. Tropical Air Masses
• 4. Maritime Air Masses

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Fronts

• When two air masses meet they do not mix very
  well because of their different temperature,
  pressure and humidity.
• Where the two air masses meet is called a Front.
• We will look at two types of Fronts, a Cold Front
  and a Warm Front.

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Cold Fronts

• A Cold Front occurs when cold air moves in
  towards warm air.
• The cold air forces the light warm air to rise.
• As the warm air rises it cools and condensation
  occurs.
• Clouds are formed and this leads to heavy
  rainfall.

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Warm Fronts

• A Warm Front develops when warm air moves in
  towards cold air.
• The warm light air rises up over the cold air.
• As it rises it cools and condensation occurs.
• Clouds are formed and this leads to rainfall.

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Depressions

• A Depression is an area of Low Atmospheric
  Pressure.
• Depressions are also known as Cyclones.
• Depression often pass over Ireland.
• Depressions bring wet and windy weather. This is
  why we receive lots of rain.

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Anticyclones

• An anticyclone is an area of high pressure.
• Anticyclones bring clear sunny weather.
• There are few clouds and a gentle breeze.

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The Water Cycle

• Water is a Renewable Resource.
• When rain falls, the water is recycled and
  eventually goes back to the clouds to fall as
  rain again.
• This is called the water cycle.
• There are 4 stages in the Water Cycle.
• Evaporation
• Condensation
• Precipitation
• Run-Off

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Clouds

• Clouds are made when water vapour condenses into
  tiny droplets.
• There are many different types of clouds.
• The most common types of clouds are
• Cirrus Clouds
• Cumulus Clouds
• Stratus Clouds

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Rainfall

• Precipitation means hail, rain, sleet or snow.
• Rain is the most common type of precipitation.
• Rain occurs when warm air is forced to rise. As
  the warm air rises it cools. Cold air cannot hold
  as much water vapour as warm air, so condensation
  occurs. Clouds are formed and rain occurs.
• There are 3 different types of rain, because
  there are 3 different reasons why warm air is
  forced to rise.
• Relief rainfall
• Frontal (cyclonic) rainfall
• Convectional rainfall

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Relief Rainfall

• Relief rainfall occurs when
• Warm moist air moves in from the sea.
• It hits a mountain range at the coast and is
  forced to rise.
• It cools as it rises.
• Condensation occurs, clouds form and it starts to
  rain.

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Frontal Rainfall

• Frontal rainfall occurs when
• Warm and cold air masses meet at a Front
• The warm air mass moves up over the cold air
  mass.
• The warm air cools and condensation takes place.
• Stratus clouds form and rain occurs.

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Convectional Rainfall

• Convectional rain occurs when
• The sun shines on the land and heats up the air
  above it.
• The heated air rises quickly.
• As it rises it cools and condensation occurs.
• Cumulus clouds are formed and heavy rain occurs.

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The Weather

• When we talk about the weather we usually talk
  about the following things.
• Temperature
• Precipitation (rain etc)
• Sunshine
• Wind speed
• Wind direction
• Atmospheric pressure
• Humidity
• All of these different aspects of the weather can
  be measured.
• There are different weather instruments to
  measure each thing.
• These instruments are usually in a weather
  station.

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Temperature

• Temperature is measured using a Thermometer.
• It is measured in degrees Celsius (C).
• Lines on a weather map showing areas of equal
  temperature are called Isotherms.

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Temperature

• You need to know how to calculate the
• 1. Mean Temperature
• 2. Temperature Range
• Mean Temperature Add all the monthly
  temperatures, then divide by 12.
• Temperature Range Take the lowest temperature
  away from the highest temperature.

Mon Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec
Mean Monthly Temp 10 13 15 17 18 21 23 28 21 15 12 11
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Precipitation

• Precipitation is measured using a Rain Gauge.
• It is measured in millimetres.
• Lines on a map showing areas of equal
  precipitation are called Isohyets.

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Sunshine

• Sunshine is measured using a Campbell Stokes
  sunshine recorder.
• Sunshine is measured in Hours per day.
• Lines on a weather map showing areas of equal
  sunshine are called Isohels.

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Wind

• We can measure 3 things about the wind.
• Wind Speed Using an Anemometer.
• Wind Direction Using a Wind Vane.
• Wind Strength Using the Beaufort Scale

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The Beaufort Scale

• The Beaufort Scale describes the effect the wind
  has on the landscape.
• Wind strength is divided into 12 forces.
• The Beaufort Scale was invented by an Irishman.

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Atmospheric Pressure

• Atmospheric pressure is measured using a
  Barometer.
• It is measured in millibars.
• Lines on a weather map showing areas of equal
  pressure are called Isobars.

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A Barograph can also be used to measure
atmospheric pressure
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Humidity

• Humidity is measured using a Hygrometer.
• A common type of hygrometer is a wet and dry bulb
  thermometer.
• It is expressed as a . 100 is the maximum.

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The Greenhouse Effect

• The Greenhouse Effect occurs naturally.
• When the sun shines it heats up the earth.
• Some of the heat gets trapped in gases in the
  atmosphere.
• It is a positive thing because without the
  Greenhouse effect the earth would be too cold for
  us to live on.

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Global Warming

• Carbon dioxide and methane are Greenhouse gases
  in the atmosphere.
• The amount of these gases has increased a lot in
  recent years.
• Therefore, more of the suns heat is being
  trapped in the atmosphere.
• This is making the earth warmer. This is called
  Global Warming.

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The Greenhouse Effect and Global Warming
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Causes of Global Warming

• There are a number of reasons why Global Warming
  is taking place.
• There is a big increase in the amount of Carbon
  dioxide in the atmosphere.
• People are burning more fossil fuels, oil, coal,
  gas.
• Tropical rainforests are being cut down. Trees
  absorb C02 and so less trees means more C02 in
  the atmosphere.
• 4. There are more CFCs in the atmosphere. These
  are bad gases which trap lots of the suns heat.

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The Effects of Global Warming

• Global warming will create many problems for
  people in the near future. These include
• The Polar ice caps will melt causing sea level to
  rise.
• Low lying countries or regions may be flooded.
• Some parts of the world will become drier. It
  will be more difficult for farmers to grow crops.
• This may lead to drought and desertification.
• However, it may also bring some positive things.
  Some countries that
• are now cold may become warmer, allowing more
  crops to be grown.

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Solutions to Global Warming

• If we want to stop the problem of global warming
  there are a number of things we need to do. These
  include
• Stop using fossil fuels such as coal and oil.
• Use more renewable energy sources such as wind,
  wave and solar power.
• Reduce Deforestation - Plant more forests and
  stop cutting down the forests we have.
• Encourage energy conservation - Save energy at
  home by using less electric items and walk /
  cycle instead of using cars or buses.

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Revision Questions

• Name 3 gases in the atmosphere.
• Why does all of the energy from the sun not reach
  planet earth?
• What does Latitude mean?
• How does Latitude influence the temperature of a
  place?
• What is wind and why does it occur?
• What is the Coriolis Effect?
• Name two Cold Ocean Currents and two Warm Ocean
  Currents.
• List 4 air masses that effect Irelands weather?
• What effect do each of these air masses have on
  Irelands weather?
• Explain with diagrams the difference between a
  Cold and a Warm Front.
• What is a Depression and what type of weather
  does it bring?
• What is an Anticyclone and what type of weather
  does it bring?
• Draw and label a diagram of The Water Cycle.

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Revision Questions

• List 3 types of clouds.
• List 3 types of rainfall and use diagrams to show
  how they are different.
• List 7 things you can measure about the weather
  and draw the instrument used to measure each
  thing.
• What is the Greenhouse Effect and why is it
  happening?
• What is Global Warming and why is it happening?
• What effects is Global Warming having on our
  planet?
• What can we do to solve the problem of Global
  Warming?