Weather

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Weather

• SOL 6.3 and 6.6

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• Identify and explain the composition, properties,
  layers, and structure of the atmosphere.
• Analyze the properties that can be observed and
  measured to predict air quality air pressure,
  humidity, moisture, and temperature and air
  quality.
• Examine evidence (charts and graphs) that
  atmospheric properties can be studied to predict
  atmospheric conditions and weather hazards
• Analyze the role of the sun in the heating and
  cooling that forms clouds and order the sequence
  of events that takes place in the formation of a
  cloud
• Relate the three states of water to the water
  cycle.
• Compare and contrast types of precipitation,
  cloud types, and relate cloud types to weather
  conditions and their location in the atmosphere
• Map the movement of cold and warm fronts, and
  interpret their effects on observable weather
  conditions. Interpret basic weather maps, and
  make forecasts based on the information
  presented.
• Compare and contrast weather-related phenomena
  including thunderstorms, tornados, hurricanes,
  and drought.
• Assess the use of technology in predicting,
  monitoring, and recording atmospheric phenomena.
  Weather satellites role
• Analyze and explain some of the effects that
  natural events (forest fires and volcanic
  eruptions) and human activities may have on
  weather, atmosphere, and climate.
• Analyze and explain the difference in average
  winter temperatures among areas in central and
  western Virginia and cities and counties along
  the Chesapeake Bay and Atlantic coast.

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Earths Energy Budget

• The Earths atmosphere is 78 nitrogen, 21
  oxygen, and the rest trace gases including
  argon, carbon dioxide, and water vapor

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Earths Energy Budget51 absorbed by the
surface19 absorbed by atmosphereRemaining 30
lost back to spaceCOPY THE PICTURE
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1. The Earth receives only a very small portion of
   the suns energy, yet this energy is responsible
   for powering the motion of the atmosphere, the
   oceans, and many processes at the Earths
   surface.
2. Incoming solar radiation is in close balance with
   the energy that leaves the atmosphere otherwise
   the Earth would heat up or cool down. Excess
   carbon dioxide and other gases may disrupt this
   balance, creating a Greenhouse Effect.
3. About 1/3 of the suns incoming energy is
   reflected back out to space. About 1/2 of the
   energy striking the Earth is absorbed by the
   surface.
4. The Earths surface is heated unequally. This is
   due to the tilt of Earth on its axis. The
   equator gets more sun the poles get less.
5. Radiation and convection from the surface
   transfer heat energy. This energy powers the
   global circulation of the atmosphere and the
   oceans on our planet. Remember that heat rises,
   cools and sinks.
6. The sun is responsible for most energy sources on
   Earth

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1. How does the amount of energy Earth receives from
   the sun compare with the energy the leaves Earth?
2. What do you predict would happen if there was a
   shortage of incoming solar radiation?
3. What would happen if Earth retained more thermal
   energy?

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Energy Transfers

• Radiation brings all of the energy to the Earth
  from the sun
• Convection currents redistribute the energy
  throughout the atmosphere and the oceans.

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Currents in the Atmosphere and Oceans

• Convection currents redistribute the energy all
  over the planet that comes from the sun. The
  average mean temperature is fairly warm because
  of these currents.

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Air Pressure

• Air pressure is the amount of air pushing down on
  us. It is measured with a barometer
• Low pressure means lousy weather, cool rainy
• High pressure means fair weather, warm sunny
• Increase in altitude decrease in air pressure

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Humidity

• Humidity is the amount of water vapor in the air
• The more humid the air is the more uncomfortable
  you feel
• 100 humidity is fog (stratus cloud formed on the
  ground)
• It is measured with a psychrometer or hygrometer
• Dew point is the temperature at which the air
  becomes 100 humid

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Atmospheric Layers

• Layers are defined by changes of temperature
• Troposphere weather takes place clouds are
  found
• Stratosphere jet stream and the ozone layer is
  found
• Mesosphere coldest and stops most meteorites
  (burn up)
• Thermosphere top most layer, it is divided into
  the ionosphere (northern lights) and the
  exosphere (satellites)

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Why Protect the Air?Watch Summarize in your
notes
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Winds are named from the direction in which they
travel from
Easterlies
Horse Latitudes
Doldrums
The Westerlies dominate the weather in the United
States. Trade winds are warm, steady breezes that
blow continuously. Wweak surface winds are _at_ the
equator, this area is called the doldrums.
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Cloud Formation
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Types of Clouds
Fair Weather Clouds
Fair now, bad weather in the next 24 hours
CIRRUS
Thunderstorm Clouds
Days of rain
Nimbostratus
Overcast drizzle
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What is weather?

• Weather is caused by the unequal heating of the
  Earths surface. Warm air rises and cool air
  sinks
• Warm air high pressure
• Cold air low pressure

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How to read a weather map
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Thunderstorms

• Thunderstorms cold meets warm front forming
  heavy rainstorms with thunder and lightning.
• When the air is heated by lightning it expands
  quickly resulting in loud sound waves (thunder).
• Lightning sudden discharge of electricity
  between cloud and cloud cloud and ground.
  Leading cause of forest fires. Can strike
  people, animals, or building.
• Safety avoid open spaces outside dont go
  under trees for shelter, avoid sinks, bathtubs,
  televisions, and telephones while inside during a
  lightning storm.

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Hurricane, Cyclone, Typhoon

• Hurricanes power cyclones that form over
  tropical areas.
• Typhoon hurricane that forms over the Pacific
  ocean.
• The eye of the storm is calm but the winds reach
  speeds of 74 to over 155 m/hr.
• High winds, storm surges, flooding, LOW PRESSURE
• Most powerful of all storms.

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Tornadoes

• Very destructive most violent
• Rotating counter-clock wise, funnel-shaped
• Develops in low, heavy cumulonimbus clouds.
• Acts like a giant vacuum cleaner
• LOW PRESSURE!!!
• Associated with severe thunderstorms
• Occur in tornado alley in the United States only

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Weather Symbols
High Pressure System Sunny weather will often
occur under high pressure
Low Pressure System lousy weather, spins counter
clockwise
Cold Front. When the cold front passes the
temperature drops and the rising air along the
front can bring precipitation
Warm Front can bring precipitation especially in
the region where the warm front is approaching.
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A stationary front has a little or no movement,
rain for days
Occluded Front cold front that overtakes a warm
front. They commonly occur close to a maturing
low pressure system
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Weather Maps
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Isobars-connect areas of equal pressure
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Weather InstrumentsCopy when I pause
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Make sure you know

1. Warm, moist air is less dense than cold, dry air,
   so it rises relative to colder, drier air.
2. Warm, moist air rises and actually gives off some
   heat as the moisture condenses
3. Air exerts pressure. Air pressure decreases with
   altitude.
4. Forest fires and volcanic eruptions are two
   natural processes that affect the Earths
   atmosphere. Many gaseous compounds particles
   are released into the atmosphere by human
   activity.
5. The amount of heat energy, water vapor, and the
   pressure of the air largely determine what the
   weather conditions are.
6. Air pressure is measured in millibars
7. The Coriolis Effect makes winds rotate to the
   right (clockwise) in the Northern Hemisphere