Ch.2 Global Climate Patterns

• The Hadley cell is the largest atmospheric circulation system on Earth, driven by solar radiation.
• minimum tilt of earth =

  22.1
• present tilt of earth =

  23.5

  
• max tilt of earth =

  24.5
• Polar cell =


  - 60 - 90

  - Easterlies

  
• ferrel cell =

  - 30 - 60 degree N/S

  - westerlies

  
• Hadley cell =

  - 0-30 degrees N/S

  - trade winds

  
• increase in latitude =

  decrease in temperature

  
• subsidence occurs at what points of latitude

  30 and 90 degrees

  
• uplift occurs at what points of latitude

  0 and 60 degrees

  
• the angle of tilt of earth's axis


  changes in cycles of about 40,000 years

  
• the shape of earth's orbit

  varies from circular to more elliptical on about a 100,000-year cycle

  
• long term climate variations are due to regular changes in

  the shape of earth's orbit and the tilt of its axis

  
• over the past 500 million years, earth's climate has fluctuated between warmer and cooler conditions several times.

  
  

  these fluctuations have influenced the


  development of ecosystems and the evolutionary history of organisms

  
• western pacific (asia and australia) becomes


  drier than normal, experiencing drought and fire

  
• eastern pacific (north and south america) becomes


  wetter than normal experiencing severe rain and flooding

  
• el nino results in

  diminished trade winds and slowing circulation in the pacific

  
• el nino events are


  associated with the equatorial pacific ocean

  
• el nino


  A warm ocean current that flows along the coast of Peru every seven to fourteen years

  
• El Nino Southern Oscillation (ENSO)

  has a frequency of about 3 to 8 years and lasts above 18 months

  
• winter solstice


  shortest day of the year

  
• at the summer solstice, the sun's rays fall directly on the

  tropic of cancer (23.5N)

  - and the sun never sets above the Arctic Circle (66.5N) and it never rises below the Antarctic Circle (66.5S)

  - this is the opposite at the winter solstice

  
• summer solstice


  longest day of the year

  
• fall equinox


  the Sun is exactly above the Equator and day and night are of equal length

  
• spring equinox


  the sun's rays shine onto the equator while the Earth sits with its axis tilted neither toward nor away from the sun

  
• at the spring and fall equinox, the sun's rays fall directly on the equator, and daylight lasts


  12 hours everywhere on earth

  
• temperate and polar zones have seasonal variation in

  solar radiation

  - this results in varying temperatures and day lengths.

  
• the differences in solar radiation between summer and winter increases from the

  tropics toward the poles

  - this results in varying temps and day lengths

  
• in the tropics, seasons are only marked by slight changes in

  precipitation and humidity

  
• only at the equator are there


  12 hours of daylight throughout the year

  
• the angle and intensity of the sun's rays striking any point on earth vary as earth


  orbits the sun

  - this results in seasonal variation in climate

  
• earth is tilted at an angle of

  23.5 degrees, relative to the sun's direct rays

  
• the Hadley, Ferrel, and polar circulation cells lead to precipitation being

  highest in the tropical latitudes and at (60 degrees N and S),while being the lowest at (30 degrees N and S) at the poles.- regional influences again create deviations from these patterns

  
• average annual temperatures become progressively cooler


  moving away from the equator, and towards the poles

  - these trends are modified by regional influences (proximity to oceans or mountain ranges)

  
• leeward side


  slope receives a little precipitation, but generally is warm and dry

  
• windward side


  slope that receives high precipitation

  
• rain shadow effect


  Precipitation falls on thewindwardside of a mountain range, resulting in lush vegetation & a warm, moist climate on one side, but a desert area on theleewardside.

  
• mountain ranges create a

  rain shadow, aka rain shadow effect

  
• when the air mass moves back down the other side of the mountain range,

  it becomes warmer and drier

  
• when an air mass meets a mountain range

  it is forced upward, cools, and releases precipitation