Chapter 14 -- Notes

Question 1

What two essential criteria must an ideal sorce region have?

Answer 1

It must be an extensice and physically uniform area. A region having highly irregular topography or one that has a surface consisting of both water and land is not satifactory.

It must be characterized by a general stagnation of atmospheric circulation so that air will stay over the region long enough to come to some measure of equilibrium with the surface.

Question 2

What are the source regions that produce the air masses that most often influence North America?

Answer 2

1. The waters of the Gulf of Mexico and Carribbean Sea and similar regions in the Pacific west of Mexico yield warm air masses.
2. The land that encompasses the southwestern United States and northern Mexico. Warm air masses.
3. The North Pacific, the North atlantic, and the snow- and ice-covered areas comprising northern North America and the adjacent Arctic Ocean. Cold air masses.

The size of the source regions and the intensity of temperatures change seasonally.

Question 3

How are air masses modified by the surface over which they are moving.

Answer 3

1. Warming or cooling from below
2. The addition or loss of moisture
3. Vertical movements