Atmospheric Circulation: Drivers and Heat Transfer

Climatological Circulation of the Atmosphere

Introduction to Atmospheric Circulation

• Climatological Circulation Defined: Refers to a long-term average of atmospheric conditions where individual weather systems and storms have been averaged out.

  • The resulting picture reveals the main, persistent wind belts of the Earth.

The Atmosphere: Structure and Composition

• Upper Boundary: Unlike oceans, the atmosphere lacks a clearly defined upper boundary; it gradually transitions into space.

• Atmospheric Pressure and Mass Distribution: The atmosphere's mass is not evenly distributed with altitude.

  • Sea Level Pressure: Approximately $1000$ millibars.

  • Mass Distribution with Altitude (referencing a graph):

    • At about 5.6 kilometers (3.5 miles) altitude, 50% of the total mass of the atmosphere is below this level.

    • By 16 kilometers (10 miles) altitude, 90% of the atmosphere's mass is below this level.

    • Commercial aircraft typically fly at altitudes around 11 or 12 kilometers.

    • Beyond 16 km, the pressure decreases exponentially, forming a long