Chapter 18

The pressure gradient force is the driving force behind wind.

Of the various elements of weather, changes in air pressure are probably the most obvious.

Horizontal movement of air is called wind.

An isobar is a line connecting places of equal humidity.

Upper air winds are generally faster than the surface winds directly below.

Closely spaced isobars indicate high wind speeds.

A southwest wind blows toward the northeast.

Low pressure systems are usually associated with clear weather.

High pressure systems are usually associated with stormy weather.

Cyclones are usually associated with stormy weather.

Anticyclones characteristically have winds blowing out from their centers.

A surface low pressure system will not strengthen unless there is high pressure aloft.

In the Northern Hemisphere, winds blow clockwise and outward from the center of anticyclones.

The region where the trade winds meet is also called the doldrums.

Most of the people living in the United States are under the influence of the wind belt known as the westerlies.

The ultimate cause of a sea breeze is the unequal heating of land and water.