Global Climate - Dry Climates

General Characteristics - deficient precipitation most of the year; potential evaporation and transpiration exceed precipitation

• occupies 26% of total land area - more than any other climate type
• evaporation > precipitation

Extent - the subtropical deserts extend from roughly 20°-30° latitude in large continental regions of the middle latitudes, often surrounded by mountains.

Major types: -

• arid (BW) - the "true desert"
  • further subdivided into BWh (hot) and BWk (cold)
  • 12% of worlds land mass
  • created by subsidence associated with semi-permanent highs
  • subsidence on lee side of mountain ranges
  • BW has highest temps in the world
  • winters can be somewhat moderate - min temps in the 20s
  • example of Phoenix AZ

Climate Map - West	Climate Map - East

• semi-arid (BS)
  • further subdivided into BSh (hot) and BSk (cold)
  • also called Steppe climate
  • short bunch grass, low bushes, sagebrush
  • similar to BW, but receives more rainfall
  • found on edges of BW regions
  • example of Denver, CO