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Climate Zones


    1.    Describe Earth's major climate zones.

    2.    Explain how climate zones are characterized.



According to the three cell convection model of each hemisphere the Earth neatly separates itself into three distinct climate zones; the polar, temperate, and the tropical zones.  As record keeping and technology advanced, a new system was developed that was based on climate controls and the evapotranspiration index of an area.  The new system is called the Kopen system named after Wladimir Koppen.  Within the system there are 5 major climate zones each with 2 or more subclimates.  Each is defined first by its temperature and second by its percipitation characteristics.


Climate Zone Subclimate Description Unique Features
Polar (E) Tundra (ET) Always cold & dry with short cold summers Covered by permafrost.  Many ponds as almost no water absorbs after rain has occured.
  Icecap (EF) Freezing temperatures all year little or no daylight in the winter, insolation is largely reflected back to space by the atmosphere and snow
  Highland (H) Temperatures vary widely with latitude, elevation and direction of exposed areas Sierra Nevada mountain range
Dry (B) Desert (BW) Less than 10 inches of rain per year with hot days.  Large temperature fluctuations between day and night. Evaporation exceeds precipitation.  Many animals are nocturnal and plants have a waxy cuticle that minimizes water loss.
  Semiarid (BS) Slightly more than ten inches per year Evaporation still exceeds precipitation.  The great plains of the midwest are an example.
Humid Tropical (A) Tropical wet (Af & Am) Hot & rainy throughout the year Closest to the equator.  Contain the tropical rain forest
  Tropical wet & dry (AW) Hot with wet & dry seasons Border the ITCZ & include the savannas. 
Moist-mid latitude - mild winters (C) Humid subtropical Hot humid summers and mild winters Southeastern US, warm moist air masses bring thunderstorms
  Marine west coast Mild and rainy all year Pacific northwest of the US
  Mediterranean Hot & dry summers and mild winters Southwest coast of the US & Mediterranean
Moist-mid latitude - severe winters (D) Humid continental warm summers and cold snowy winters Inland northeastern US
  Subarctic Short summers and long snowy winters  

(ess.geology.ufl.edu/ess/Notes/ Climatology/worldclimate.jpeg)

(geography.sierra.cc.ca.us/.../ 2_atmosphere/koppen.jpg)

Causes for climate alteration:

Earth's motions - Earth's orbit (100,000), tilt (41,000), and wobble (23,000) affect insolation
Plate tectonics - Continents move to different latitudes affecting insolation
Sunspots - may relate to Earth's changing temperatures
Volcanoes - Volcanic winter, acid rain from SO2 in the atmosphere
Global warming - increases temperatures and moves precipitation belts






Last modified: February 02, 2004