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