Meteorology

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Meteorology

• The Science dealing with the atmosphere and
  weather

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Atmosphere

• The layer of gases surrounding the Earth
• 78 Nitrogen
• 21 Oxygen
• Everything else 1 combined

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Weather

• The changes which occur in the atmosphere.
  Weather changes constantly
• The Earths attempt at balancing its heat and
  moisture
• Climate- The average weather conditions in a
  specific area at a specific time of year.

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The Atmosphere

• Divided into four major layers according to the
  relationship between temperature and elevation

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The layers of the Atmosphere

• Troposphere- The layer we live in and where all
  the weather reported occurs in. Inverse
  relationship between temperature and elevation
• Stratosphere-The layer which contains the Jet
  Stream and the Ozone layer- Direct relationship
  between temperature and elevation.

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Layers of the Atmosphere

• Mesosphere- coldest layer of the atmosphere.
  Responsible for the burning up of meteors due to
  friction. Inverse relationship between
  temperature and elevation.
• Thermosphere-warmest layer of the atmosphere.
  Thinnest layer of the atmosphere. Contains two
  sublayers-the Ionosphere which allows for
  worldwide radio communication, and the Exosphere
  which is where manmade satellites orbit the
  Earth.

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Importances of the Atmosphere

• Protection from scorching
• Protection from freezing to death (Greenhouse
  effect)
• Protection from bombardment by meteorites
• Protection from Ultraviolet rays (ozone) and
  other deadly rays from the sun (magnetosphere)
• Provider of Oxygen and Carbon Dioxide for living
  things (Photosynthesis and Respiration)
• Provider of water Water cycle
• Provider of Nitrates and nitrites for living
  things- Nitrogen cycle

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Hydroglogic (water) Cycle

• Evaportation
• Respiration
• Transpiration
• Condensation
• Precipitation
• Absorbtion
• Runoff

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Nitrogen Cycleprovider of nitrogen for living
things(DNA, protein)

• Lightning
• Precipitation
• Nitrogen fixing bacteria
• animal waste
• Animal/plant decomposition
• Denitrifying bacteria
• Volcanic eruption

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Carbon Dioxide/Oxygen Cycle

• Photosynthesis
• Respiration
• Fires
• Automobiles
• Factories
• Decomposition

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Four factors that interract to create weather

• Heat
• Pressure
• Wind
• Moisture

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Heat

• Kinetic theory of heat
• Transfer of Heat
• Conduction
• Radiation
• Convection

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Measuring Heat

• Thermometer
• Max-min thermometer

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Pressure

• Weight of the atmosphere
• 14.7 pounds/square inch
• 29.92 inches of Mercury
• 1013.2 Millibars
• Measured with the Barometer (Mercury or Aneroid)
• Barograph- measures and records air pressure

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Relationships with Pressure

• Temperature and Pressure- Inverse- warm air
  expands and becomes less dense and rises in
  cooler, more dense air.
• Elevation and Pressure-Inverse-If air pressure is
  the weight of the atmosphere, then going higher
  would have less air above to cause pressure.
• Humidity and Pressure- Inverse- High humidity
  air weighs less than dry air because a water
  molecule (18 amu) weighs less than a Nitrogen
  molecule (28 amu) or an Oxygen molecule (32 amu)
  it replaces.

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Pressure Gradient Force

• Wind is caused by differences in pressure. The
  amount of difference causes the wind to move
  faster (steep gradient) or slower (shallow
  gradient) between Isobars (lines of equal
  pressure on a weather map.
• Wind always moves from High pressure (H) to low
  pressure (L)
• General rule- High pressure- fair weather
• Low pressure or dropping pressure poor weather

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Moisture

• Any form of water in the air- rain,
  sleet,(liquids),snow (solid), hail, humidity
  (gas).
• Humidity is the amount of water vapor in the air.
• Relative humidity is the amount of water vapor in
  the air compared to the maximum possible at a
  given temperature.

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Relative Humidity

• Warm air expands and can hold more water vapor
  than cool air. If the actual water vapor in the
  air remains the same, the relative humidity will
  actually go down as the air heats up.
• R.H. actual water vapor in air/maximum humidity
  possible at the given temperature

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Relative humidity terms

• Dew point- the temperature at which air becomes
  saturated or 100 R.H.
• Capacity- The amount of water vapor that the air
  can hold at a given temperature
• Saturation point- same as dew point
• Super saturated air- when temperature falls below
  the dew point.
• Dew- when dew point is reached and it is above
  freezing, water vapor condenses on grass, leaves,
  cars, tents etc.

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Relative Humidity -

• Frost- when the dew point is reached and is below
  freezing frost forms by Sublimation.
• Snow also forms by sublimation. Notice the
  crystalline structure to both snow and frost.

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Phase changes

• Melting-change from a solid to a liquid (heat
  absorbed)
• Freezing-change from a liquid to a solid (heat
  given off)
• Evaporation- change from a liquid to a gas (heat
  given off
• Condensation-change from a gas to a liquid (heat
  absorbed)
• Sublimation- change directly from a solid to a
  gas (absorbed) or a gas to a solid(given off)
  (dry ice, snow, frost)

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Moisture Instruments

• Rain guage
• Psychrometer
• Hygrometer
• Snow stick

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Fronts

• Boundary between two different air masses- result
  in changes in the weather
• Cold front- when a cold air mass overtakes a warm
  air mass- forcing it up- stormy weather for a
  short period of time
• Warm front- when a warm air mass moves up and
  over a cold air mass- longer periods of rain

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Fronts

• Stationary front- when a cold air mass and a warm
  air mass meet and stop- many days of rain.
• Occluded front- When a warm air mass is blocked
  on either side by two cold air masses and is
  forced upwards. Many days of rain.

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Clouds

• Classified by shape and altitude
• Cumulus clouds- Cotton ball clouds, fair weather
  clouds
• Stratus clouds- layered clouds- fog is a stratus
  cloud on the ground
• Cirrus clouds- high clouds, thin and wispy. Fair
  weather- made of ice.
• Nimbus clouds- thunderstorm clouds dark and
  threatening.

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Weather forecasting

• Weather stations
• Satellites
• Radar
• Doppler radar
• Weather balloons
• Forecasts are accurate when they are made- the
  problem is that weather constantly changes the
  four factors affect one another- when one changes
  they all change.