Atmospheric Circulation

Primary High- and Low-Pressure Areas

Equatorial Low-Pressure Trough

Circulation Pattern
  1. 0°+-
  2. Constant high levels of insolation
  3. Heating of air
  4. Air rises
  5. Low pressure
  6. In upper atmosphere air moves outward to 30 degrees N and S latitude

Polar high pressure cells

Circulation Pattern
  1. 90°N and S
  2. Low average insolation
  3. Intense cooling of atmosphere
  4. Cold air descends
  5. Surface air flows out toward sub polar region

Subtropical high-pressure cells

Circulation Pattern
  1. Descending air at 30 N and S latitude
  2. Surface flow out toward equator and poles
  3. Drives predomonant winds
    • northeast trade winds in the tropics
    • prevailing westerlies in midlatitudes

Subpolar low pressure cells

Circulation Pattern
  1. 60° N and S latitude
  2. Surface air flows in from subtropical high and polar high
  3. Converging air rises