Weather and Climate

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Weather and Climate
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• Weather is the condition of the bottom layer of
  the earths atmosphere in one place over a short
  period of time.
• Weather is the day-to-day conditions of a
  particular place.

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• Climate is the term for weather patterns that an
  area typically experiences over an extended
  period of time.
• Temperatures, precipitation, seasons, etc.

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What factors influence climate?

• The movement of the earth on its axis is called
  rotation.
• One complete orbit around the sun is called a
  revolution.

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• Earths rotation and tilt

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Latitude effects climate
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• Equinox When the earth is not tilted and the
  suns rays fall directly on the equator.
• Actually means Equal night. Around March 21
  and September 23

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• Tropic of Cancer 23 ½ degrees N, the
  northernmost point on the Earth to receive direct
  rays of the sun
• Tropic of Capricorn 23 ½ degrees S, the
  southernmost point on the Earth to receive direct
  rays of the sun

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• Solstice When the suns rays hit the tropic of
  Cancer. The farthest tilt north and is the
  beginning of summer in the Northern H. and the
  beginning of winter in the Southern H. (around
  June 21).
• When the earth tilts the other way we have the
  opposite. Around Dec. 22)

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The Poles

• Because of the earths tilt the poles have
  continuous sunlight or darkness for six months
  out of the year.
• March 20 September 23
• September 23- March 20

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• The greenhouse effect traps solar radiation as
  heat within the atmosphere.

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Factors Effecting Climate
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Low Latitudes

• Between 30 Degrees N and 30 degrees S latitude.
• Receive direct sunlight year round
• Warm and hot climates

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High Latitudes

• The earths polar regions (between 60 and 90
  degrees latitude)
• Arctic Circle and Antarctic Circle (66 ½ degrees
  latitude)
• Have 6 months of sunlight and 6 months of
  darkness

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Mid Latitudes

• Between 30 and 60 degrees latitude
• A temperate climate, ranging from fairly hot to
  fairly cold
• Dramatic seasonal changes.

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• Elevation
• Air temperature decreases at a rate of 3.5 F for
  every 1000 feet in elevation.
• Mount Kilimanjaro is located almost on the
  equator but has snow caps year round.

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Mt. Kilimanjaro
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Wind

• Wind is caused by air flowing from high pressure
  to low pressure. Since the Earth is rotating,
  however, the air does not flow directly from high
  to low pressure, but it is deflected to the right
  (in the Northern Hemisphere to the left in the
  Southern Hemisphere), so that the wind flows
  around the high and low pressure areas.
• For small, short-lived systems (such as in the
  cold outflow of a thunderstorm) the wind will
  flow directly from high pressure to low pressure.
  
• video

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• Prevailing Winds Global winds that blow in a
  fairly constant pattern.
• Doldrums At the equator, global winds are
  diverted north and south, leaving a narrow,
  generally windless band know as the doldrums

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Oceans and climate

• Water heats and cools slower than land.
• Oceans tend to have a moderating effect on
  climate, meaning that places close to oceans
  dont have as extreme differences between their
  warmest and coldest days.

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Ocean currents

• Cold and warm streams of water that move through
  the oceans.
• Ocean currents affect climate in the coastal
  areas in which they flow

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Precipitation

• Humidity The amount of water vapor contained in
  the atmosphere.
• Precipitation is the forms of water that fall
  from the atmosphere to the earths surface.
• Rain, snow, hail, sleet,

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What causes precipitation

• Precipitation forms when air temperature changes.
• Warm air holds more water than cold air.
• When air cools it can no longer hold as much
  water. Tiny droplets of water gather together an
  form clouds.
• Precipitation forms when more water collects in
  clouds then they can hold.

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Convectional precipitation

• In convectional precipitation, unequal heating of
  the surface causes an air parcel to become warmer
  and less dense than the surrounding air. Because
  it is less dense, it rises. As it moves upward,
  it cools, and condensation with precipitation may
  occur.

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Frontal precipitation

• Frontal precipitation results when the leading
  edge( front) of  a warm air mass meets a cool air
  mass. The warmer air mass is forced up over the
  cool air. As it rises the warm air cools,
  moisture in the air condenses and forms clouds,
  resulting in precipitation.

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Orographic Precipitationalso called the Rain
Shadow Effect

• Orographic precipitation results when warm moist
  air of the ocean is forced to rise by large
  mountains. As the air rises it cools, moisture in
  the air condenses and clouds and precipitation
  result on the windward side of the mountain while
  the leeward side receives very little.

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Leeward side
Windward side
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El Nino

• The periodic change in the pattern of ocean
  currents, water temperatures, and weather in the
  mid-Pacific region
• It doesnt occur every year but is occurring more
  frequently.
• It affects climate around the world.
• Video

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Climate Regions

• Climates are organized into 5 regions tropical,
  dry, mid latitude, high latitude, and highland
• These large regions are divided into further
  climate zones

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Tropical Climates

• Tropical climates found in low latitudes include
  tropical wet and tropical dry
• Tropical wet climates are hot (80 F) and have
  high rainfall all year
• Tropical dry climates have dry winters and wet
  summers, along with high temperatures year-round

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Dry Climates

• Two types of dry climates are desert and steppe
• Deserts have little rainfall and temperature
  varies from heat in the day to cool at night
• Natural vegetation includes scattered shrubs and
  cacti
• Often bordering deserts are steppes, dry largely
  treeless grasslands

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Mid Latitude Climates

• Marine west coast on western coastlines that
  have cool summers and abundant rainfall
• Mediterranean Mild rainy winters and hot dry
  summers
• Humid subtropical Short, mild winters and
  year-round rain
• Humid continental warm summers and cold winters
  with varying precipitation

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High Latitude Climates

• Subarctic climates experience bitterly cold
  winters and short, cool summers
• Permafrost, a thin layer of soil beneath the
  surface is permanently frozen
• Tundra regions are closer to the Poles and have
  dark, bitter winters
• Ice cap regions are covered often by 2-3 miles of
  snow and ice

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Highland Climates

• High mountain areas experience year-round cold
  temperatures because of elevation
• These can be found in any latitude zone where
  mountains are high enough

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