Deck 8: Air Pressure and Winds

Question 1

​Surface winds that blow over the ocean are closer to being geostrophic than those that blow over land.

Answer 1

True

Question 2

​It takes a larger column of cold, more-dense air to exert the same surface pressure as a taller column of warm, less-dense air.

Answer 2

False

Question 3

​Hydrostatic equilibrium does not exist in violent thunderstorms and tornadoes, where the air shows appreciable vertical acceleration.

Answer 3

True

Question 4

The angle at which surface winds cross isobars is to a large degree dependent on the roughness of the terrain.
​

Question 5

​Flights from San Francisco to New York City take, on average, about 30 to 45 minutes less than the return flights.

Question 6

​Air pressure decreases with height more rapidly in cold air than in warm air.

Question 7

​The pressure gradient force is non-existent at the equator.

Question 8

​In middle latitudes, surface pressure changes are primarily the result of large high- and low-pressure areas that move toward or away from a region.

Question 9

​On an isobaric weather chart, the spacing of the height contours indicates the magnitude of the pressure gradient force.

Question 10

​The Coriolis force is the force that causes the wind to blow.

Question 11

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
E) ​remain the same; remain the same

Question 12

​Surface pressure is unaffected by the relationship between upper-level divergence and surface convergence.

Question 13

​100 pascals equals 10 millibar.

Question 14

Station pressure and sea-level pressure can never be the same value.

Question 15

​If you (in the Northern Hemisphere) stand with the wind aloft to your back, lower pressure will be to your right and higher pressure to your left.

Question 16

​The pressure gradient force has a direct effect on horizontal wind movements.

Question 17

​In the Northern Hemisphere, the average height of contour lines on an upper-level isobaric chart tend to decrease northward.

Question 18

In the tropics, daily (diurnal) fluctuations of pressure appear to be due primarily to the absorption of solar energy by ozone in the upper atmosphere and by water vapor in the lower atmosphere.

Question 19

​The altimeter and barograph are two types of aneroid barometers.

Question 20

​The angle at which surface winds cross isobars depends upon surface friction, wind speed, and the height above the surface.

Question 21

The unit of pressure most commonly found on a surface weather map is​

A) ​inches of mercury.
B) ​millibars or hectopascals.
C) ​pounds per square inch.
D) ​atmospheres.
E) ​torr.

Question 22

A ridge on an upper-level isobaric chart indicates​

A) ​higher-than-average heights.
B) ​lower-than-average heights.
C) ​average heights.
D) ​a region with calm winds.
E) ​a region with strong winds.

Question 23

If two air parcels at sea level have the same size but different temperatures, the colder parcel of air will have​

A) ​a higher pressure but the same density as the warm parcel.
B) ​the same pressure but lower density than the warm parcel.
C) ​the same pressure but higher density than the warm parcel.
D) ​a lower pressure but the same density as the warm parcel.
E) ​the same pressure and the same pressure as the warm parcel.

Question 24

To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for​

A) ​temperature.
B) ​altitude.
C) ​density.
D) ​gravity.
E) ​humidity.

Question 25

​Lines connecting points of equal pressure are called

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

Question 26

On a 500 millibar chart, ____ are drawn to represent horizontal changes in altitude which correspond to horizontal changes in pressure.​

A) ​contour lines
B) ​isobars
C) ​isotherms
D) ​isotachs
E) ​isofiles

Question 27

Suppose a parcel of air has a given temperature, pressure, and density. If the parcel's size remains the same while its temperature increases, then the air pressure inside the parcel will​

A) ​decrease.
B) ​decrease, but will not drop below 1,000 mb.
C) ​increase.
D) ​remain constant.
E) ​decrease to well below 1,000 mb.

Question 28

Warm air aloft is associated with constant pressure surfaces that are found at ____ altitudes than normal and ____ normal atmospheric pressure aloft.​

A) ​higher; higher than
B) ​higher; lower than
C) ​lower; higher than
D) ​lower; lower than
E) ​lower; the same as

Question 29

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.

Question 30

​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
E) ​1,340 mb

Question 31

On an upper-level chart the wind tends to be​

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.
E) ​at an angle between 10 and 30 to the contours and towards higher pressure.

Question 32

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
E) ​divergence

Question 33

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

A) ​wind speed.
B) ​pressure.
C) ​density.
D) ​wind direction.
E) ​temperature.

Question 34

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 ____ in the cold column.​

A) ​decrease; at the same rate as
B) ​decrease; more slowly than
C) ​increase; more rapidly than
D) ​increase; more slowly than
E) ​increase; at the same rate as

Question 35

Isobaric surfaces are ____ in warm, less-dense air and ____in cold, more-dense air.​

A) ​lower; higher
B) ​higher; lower
C) ​constant; unstable
D) ​unstable; constant
E) ​nonexistent; stable

Question 36

On an isobaric surface,

A) ​altitude is constant.
B) ​temperature is constant.
C) ​pressure is constant.
D) ​precipitation is constant.
E) ​cloud coverage is constant.

Question 37

The amount of pressure change that occurs over a given horizontal distance is called the​

A) ​pressure tendency.
B) ​Coriolis parameter.
C) ​pressure gradient.
D) ​potential gradient.
E) ​slope.

Question 38

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.
E) ​more rapidly in the horizontal over land than over the ocean.

Question 39

Horizontal pressure variations cause air to move from areas of _____ pressure to areas of ____ pressure.​

A) ​high; low
B) ​low; high
C) ​low; low
D) ​high; high
E) ​high; higher

Question 40

Which of the following instruments measures pressure?​

A) ​barometer
B) ​thermometer
C) ​radiometer
D) ​hygrometer
E) ​densitometer

Question 41

Winds blow slightly inward​

A) ​around surface low pressure centers in the Northern Hemisphere only.
B) ​around surface low pressure centers in the Southern Hemisphere only.
C) ​around surface low pressure centers in the Southern Hemisphere only.
D) ​at the poles in both hemispheres.
E) ​at the equator.

Question 42

Zonal flow wind-flow patterns are associated with​

A) ​north-to-south flows.
B) ​south-to-north flows.
C) ​east-to-west flows..
D) ​west-to-east flows.
E) ​random directional flows.

Question 43

The ____ force is an apparent force created by Earth's rotation.​

A) ​pressure gradient
B) ​Coriolis
C) ​centripetal
D) ​gravitational
E) ​frictional

Question 44

Which of the following produces the strongest Coriolis force?​

A) ​fast winds; low latitude
B) ​fast winds; high latitude
C) ​slow winds; low latitude
D) ​slow winds; high latitude
E) ​fast winds; intermediate altitude

Question 45

In an aneroid barometer, a general rule is that the higher the reading, the more likely ____ weather will occur, and the lower the reading, the better the chances are for ____ weather.​

A) ​clear; inclement
B) ​inclement; clear
C) ​cold; warm
D) ​windy; still
E) ​snowy; rainy

Question 46

Surface winds blow across isobars at an angle and the pressure gradient force is balanced by the ____ force and the Coriolis force.​

A) ​surface
B) ​pressure gradient
C) ​frictional
D) ​centripetal
E) ​gravitational

Question 47

What is considered standard sea-level atmospheric pressure in millibars?​

A) ​101.25 mb
B) ​103.25 mb
C) ​1013.52 mb
D) ​1031.25 mb
E) ​1013.25 mb

Question 48

In the tropics, pressure rises and falls in a regular pattern ____ a day.​

A) ​once
B) ​twice
C) ​three times
D) ​four times
E) ​ five times

Question 49

There is always a strong pressure gradient force directed _________.​

A) ​northward
B) southward
C) ​eastward
D) ​westward
E) ​upward

Question 50

A geostrophic wind is a wind that results from a balance between the ____ force and the ____ force.​

A) ​pressure gradient; gravitational
B) ​pressure gradient; frictional
C) ​Coriolis; gravitational
D) ​Coriolis; frictional
E) ​Coriolis; pressure gradient

Question 51

The unit of pressure designated by the International System (SI) of measurement is the ____.​

A) ​atmospheric pressure
B) ​millibar
C) ​bar
D) ​torr
E) ​pascal

Question 52

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.
E) ​clockwise and parallel to the center.

Question 53

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

A) ​north
B) ​southwest
C) ​east
D) ​west
E) ​northeast

Question 54

The wind around a surface low pressure center in the Southern 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.
E) ​clockwise and either outward or inward.

Question 55

In middle latitudes, when an area of high pressure approaches a city, surface pressure usually ____. When it moves away, pressure usually ____.

A) ​remains the same; remains the same
B) ​remains the same; falls
C) ​remains the same; rises
D) ​falls; rises
E) ​rises; falls

Question 56

The winds aloft in the middle latitudes of the Southern Hemisphere generally blow​

A) ​from west to east.
B) ​from east to west.
C) ​from north to south.
D) ​from south to north.
E) ​in any of the above directions.

Question 57

Meridional wind-flow patterns go​

A) ​from either north-to-south or south-to-north.
B) ​from north-to-south.
C) ​from south-to-north.
D) ​from east-to-west.
E) ​from either east-to-west or west-to-east.

Question 58

On a sunny day, an aneroid barometer would indicate "____" weather when carried to the top of a hill or mountain.​

A) ​fair
B) ​sunny
C) ​cold
D) ​wet
E) ​stormy

Question 59

Upper-level winds in the middle latitudes of both hemispheres generally blow from ____.​

A) ​the north
B) ​the east
C) ​the south
D) ​the west
E) ​changing directions

Question 60

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.
E) ​gravitational force.

Question 61

The most common type of home barometer is called the ____________________ barometer.

Question 62

A pascal (Pa) is the force of ____ acting on a surface area of ____.​

A) ​1 Newton; 1 square meter
B) ​100 Newton; 1 square meter
C) ​1 Newton; 1 square foot
D) ​1 Newton; 1 square inch
E) ​10 Newton; 1 square foot

Question 63

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

Question 64

Warming and cooling of air creates density oscillations known as ____________________ that show up as small pressure changes near Earth's surface.

Question 65

Atmospheric air pressure always ____________________ with height.

Question 66

The friction layer usually extends upward to an altitude near ____ above the surface.​

A) ​100 m
B) ​200 m
C) ​1,000 m
D) ​1,500 m
E) ​2,000 m

Question 67

A rapid change in pressure over a relatively short distance is called a ____ pressure gradient.​

A) ​sudden
B) ​rapid
C) ​weak
D) ​gentle
E) ​steep

Question 68

If you live in the Northern Hemisphere and a region of surface low pressure is directly west of you, the surface wind direction at your home would probably be either ____________________ or _____________________.

Question 69

On an upper-level chart cold air aloft is generally associated with ____________________ pressure.

Question 70

Because water is 13.6 times less dense than mercury, an atmospheric pressure of 76 cm (30 in.) of mercury would be equivalent to 1034 cm (408 in.) of water. Therefore, a water barometer resting on the ground near sea level would have to be read from a ladder over ____ tall.​

A) 5 m (16 ft)
B) ​10 m (33 ft)
C) ​15 m (49 ft)
D) ​20 m (66 ft)
E) ​25 m (82 ft)

Question 71

If upper-level divergence exceeds surface convergence, the air pressure at the center of the surface low will​

A) ​be unaffected.
B) ​double.
C) ​triple.
D) ​increase.
E) ​decrease.

Question 72

Because of friction, surface winds move ____ winds aloft with the same pressure gradient.​

A) ​more slowly than
B) ​at the same speed as
C) ​faster than
D) ​twice as fast as
E) ​at half the speed as

Question 73

The Coriolis force deflects winds to the ____________________ in the Northern Hemisphere and to the ____________________ in the Southern Hemisphere.​

Question 74

The Coriolis force acts at a ____ degree angle to the wind​.

A) ​10
B) ​20
C) ​30
D) 45
E) 90 ​

Question 75

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

Question 76

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

Question 77

The magnitude of the Coriolis force varies with ____ and ____.​

A) ​wind speed; longitude
B) ​wind flow; precipitation
C) ​altitude; latitude
D) ​wind speed; latitude
E) ​wind direction; hemisphere

Question 78

If Earth did not rotate, the wind would blow directly from regions of ____________________ pressure toward regions of ____________________ pressure.

Question 79

Which pressure unit is most commonly used in aviation?​

A) ​bar
B) ​millibar
C) ​torr
D) ​pascal
E) ​inches of mercury

Question 80

The vertical pressure gradient force is directed ____________________.