Atmospheric motion principles

Learning objectives

When you have read this chapter you will:

Know the basic laws of horizontal motion in the atmosphere, Know how the Coriolis force arises and its effects, Be able to define the geostrophic wind,

Know how friction modifies wind velocity in the boundary layer,

Understand the principles of divergence/convergence and vorticity and their roles in atmospheric processes,

Understand the thermodynamic, dynamic and topographic factors that lead to distinctive local wind regimes.

The atmosphere is in constant motion on scales ranging from short-lived, local wind gusts to storm systems spanning several thousand kilometres and lasting for about a week, and to the more or less constant global-scale wind belts circling the earth. Before considering the global aspects, however, it is important to look at the immediate controls on air motion. The downward-acting gravitational field of the earth sets up the observed decrease of pressure away from the earth's surface that is represented in the vertical distribution of atmospheric mass (see Figure 2.13). This mutual balance between the force of gravity and the vertical pressure gradient is referred to as hydrostatic equilibrium (p. 23). This state of balance, together with the general stability of the atmosphere and its shallow depth, greatly limits vertical air motion. Average horizontal wind speeds are of the order of one hundred times greater than average vertical movements, although individual exceptions occur - particularly in convective storms.

Continue reading here: Laws Of Horizontal Motion

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  • carola lucchese
    What is scales of atmospheric motion?
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  • kerstin
    What are the principles of atmospheric motion?
    4 years ago