Deck 7: Atmospheric Motions

Question 1

The pressure gradient force is directed from higher pressure toward lower pressure:

A)only at the equator.
B)at all places on earth except for the equator.
C)only in the Northern Hemisphere.
D)only in the Southern Hemisphere.
E)at all places on earth.

Answer 1

E

Question 2

On an isobaric weather chart,the spacing of the height contours indicates the magnitude of the __________ force.

A)pressure gradient
B)Coriolis
C)thermal

Answer 2

A

Question 3

The _________ force is the force that causes the wind to blow.

A)Coriolis
B)pressure-gradient
C)friction

Answer 3

B

Question 4

On an upper-level chart,normally we find warm air associated with __________ pressure,and cold air associated with __________ pressure.

A)high,high
B)high,low
C)low,low
D)low,high

Question 5

A surface low pressure center is generally associated with __________ on an upper level isobaric chart.

A)a trough
B)a ridge
C)zonal flow
D)convergence

Question 6

Net convergence of air would cause surface pressure to __________ and net divergence would cause surface pressure to __________.

A)increase,decrease
B)increase,increase
C)decrease,decrease
D)decrease,increase

Question 7

The contour lines drawn on a 500 mb chart are lines of constant:

A)pressure.
B)altitude.
C)density.
D)wind direction.

Question 8

On an isobaric surface,

A)altitude is constant.
B)temperature is constant.
C)pressure is constant.
D)both a and c

Question 9

A station at an altitude of 900 m (about 3,000 feet)above sea level measures an air pressure of 930 mb.Under normal conditions,which of the values below do you think would be the most realistic sea level pressure for this station?

A)840 mb
B)930 mb
C)1,020 mb
D)1,830 mb

Question 10

Low __________ on a constant height chart corresponds to low __________ on a constant pressure chart.

A)pressures,pressures
B)pressures,heights
C)heights,pressures
D)heights,heights

Question 11

On an upper-level chart the wind tends to blow:

A)at right angles to the isobars or contour lines
B)parallel to the isobars or contours
C)at an angle between 10 and 30 to the contours and towards lower pressure
D)at constant speed

Question 12

Lines connecting points of equal pressure are called:

A)isobars.
B)millibars.
C)contours.
D)isotherms.
E)a coordinate grid.

Question 13

Pressure changes:

A)more rapidly in the horizontal direction than in the vertical.
B)more rapidly in the vertical direction than in the horizontal.
C)at the same rate in the horizontal and vertical directions.
D)more rapidly in the vertical over land than over the ocean.

Question 14

The force that would cause a stationary parcel of air to begin to move horizontally is called the:

A)Coriolis force.
B)pressure gradient force.
C)centripetal force.
D)frictional force.

Question 15

If the earth's gravitational force were to increase,atmospheric pressure at the ground would:

A)increase.
B)decrease.
C)remain the same.
D)cause the atmosphere to expand vertically.

Question 16

Which of the following can influence wind direction?

A)Coriolis force
B)pressure gradient force
C)centripetal force
D)all of the above

Question 17

Which of the following forces can not act to change the speed of the wind?

A)pressure gradient force
B)frictional force
C)Coriolis force
D)none of the above

Question 18

If a liquid with a lower density than mercury were used in a barometer the height of the column in the barometer would:

A)increase.
B)decrease.
C)remain the same.
D)not provide an accurate measure of atmospheric pressure.

Question 19

The surface pressures at the bases of warm and cold columns of air are equal.Air pressure in the warm column of air will __________ with increasing height __________ than in the cold column.

A)decrease,more rapidly
B)decrease,more slowly
C)increase,more rapidly
D)increase,more slowly

Question 20

Warm air aloft is associated with constant pressure surfaces that are found
At __________ altitude than normal and __________ than normal atmospheric pressure aloft.

A)higher,higher
B)higher,lower
C)lower,higher
D)lower,lower

Question 21

If,at your home in the Northern Hemisphere,the surface wind is blowing from the northwest,then the region of lowest pressure will be to the east of your home.

Question 22

The vertical pressure gradient force is directed downward.

Question 23

Surface winds blow across the isobars at an angle due to the frictional force.

Question 24

Fast winds at high latitudes produce the strongest Coriolis force.

Question 25

Winds blow slightly inward around surface low pressure centers in the Southern Hemisphere.

Question 26

Suppose that the winds aloft are geostrophic and blowing from the north.With the same orientation of isobars at the surface,the winds would blow from the southeast.

Question 27

The rate of the earth's rotation determines the strength of the pressure gradient force.

Question 28

Suppose that the winds aloft are geostrophic and blowing from the north.Low pressure is located to the east.

Question 29

The wind around a surface high pressure center in the Northern Hemisphere blows:

A)counterclockwise and outward from the center.
B)counterclockwise and inward toward the center.
C)clockwise and outward from the center.
D)clockwise and inward toward the center.

Question 30

Sketch the wind flow patterns around surface high and low pressure centers in both the Northern and Southern Hemispheres.

Question 31

The surface air around a strengthening low pressure area normally __________,while aloft,above the system,the air normally __________.

A)diverges,diverges
B)diverges,converges
C)converges,converges
D)converges,diverges

Question 32

The Coriolis force is strongest at the equator.

Question 33

The atmosphere around the earth would rush off into space if the vertical pressure gradient force were not balanced by:

A)the Coriolis force.
B)the horizontal pressure gradient force.
C)gravity.
D)the centripetal force.
E)friction.

Question 34

Suppose you deflate a fully-inflated bicycle tire by depressing the air valve.Why does air rush out of the tire? Why does the rushing air feel cold? After the air stops rushing out of the tire,is the tire empty? Explain your answer.

Question 35

What differences might you expect to see between the weather conditions depicted on the surface in your city and at the 500 mb level above your city?

Question 36

Under what conditions (if any)might you record a station pressure of 750 mb?

Question 37

Suppose you stand outside and feel a fresh breeze blowing against your face.Could this be a geostrophic wind? Explain.

Question 38

If the earth stopped rotating there would no longer be a Coriolis force.

Question 39

We can generally expect the air to be __________ above areas of surface low pressure and __________ above areas of surface high pressure.

A)rising,rising
B)rising,sinking
C)sinking,sinking
D)sinking,rising

Question 40

Briefly explain the principle of the mercury barometer.Mercury is relatively expensive and toxic.Why do you think mercury is used in barometers instead of another fluid such as water?

Question 41

Explain briefly why upper-level winds at middle latitudes in the Northern Hemisphere generally blow from west to east.In what direction do upper level winds at middle latitudes in the Southern Hemisphere blow?

Question 42

Explain why it is often windy at the beach.What forces are responsible,and how do beachfront conditions differ from conditions farther inland?

Question 43

If the earth did not rotate,how would you expect winds to blow with respect to high and low pressure centers?

Question 44

Explain why strong upper-level divergence will cause the pressure in the center of a surface low to decrease.

Question 45

Explain why closely-spaced contour lines on an upper-level isobaric chart are associated with fast winds.