1.

Destabilization of the atmosphere that can cause thunderstormson the west coast of the U.S. occurs primarily due to:

a. warming of the upper levels of the troposphere

b. warming of the lower levels of the troposphere

c. cooling of the lower levels of the troposphere

d. cooling of the upper levels of the troposphere

On an upper-air constant pressure surface, a dip in the heightlines toward the equator is called a ___________, while a bulge inthe height lines toward the poles is a _________.

a. trough, ridge

b. ridge, trough

c. jet streak, jet stream

To approximately locate the jet stream on a map of heightcontours at the 300-mb level, look for ____________

a places where the height lines spread apart

b places where the height lines have their highest values

c places where the height lines have their lowest values

d places where the height lines are closest together