Deck 8: Air Pressure and Winds

Question 1

On an upper-level chart, which of the following is generally associated with a centre of surface low pressure?

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

Answer 1

B

Question 2

What is the direction of the pressure gradient force during a reversible adiabatic process, in relation to the isobars?

A)perpendicular
B)pointing to the left of the isobars
C)parallel
D)pointing to the right of the isobars

Answer 2

C

Question 3

Which of the following is the unit of pressure most commonly found on a surface weather map?

A)inches of mercury
B)atmospheres
C)pounds per square inch
D)hectopascals

Answer 3

D

Question 4

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following describes the temperature of the air at point A compared to the air at point B?

A)It is warmer than the air at point B.
B)It is colder than the air at point B.
C)It is the same temperature as the air at point B.

Question 5

Which of the following factors generates the Coriolis force?

A)gravitational force exerted by the moon as it orbits the Earth
B)day/night temperature contrasts
C)wind
D)the rotating Earth

Question 6

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following terms refers to the amount of pressure change that occurs over a given horizontal distance?

A)pressure tendency
B)pressure gradient
C)Coriolis parameter
D)potential gradient

Question 7

Equilibrium between which of the following factors is described by the hydrostatic equation?

A)vertical pressure gradient force and gravity
B)friction force and gravity
C)Coriolis force and gravity
D)horizontal pressure gradient force and gravity

Question 8

Given the equation for geostrophic wind is , which of the following will increase the wind speed?

A)increasing the value of the pressure( )
B)increasing the angular spin of the Earth ( )
C)decreasing the value of the pressure difference( )
D)decreasing the value of the latitudinal factor (sin )

Question 9

North
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Consider the scenario in which a pilot is flying from warm air into cooler air, but the altimeter indicates the same altitude in the cold air as is did in the warm air. Which of the following describes the altitude of the plane?

A)higher than before
B)lower than before
C)at the same altitude as before
D)initially higher, then lower than before

Question 10

The spacing of the height contours on an isobaric weather chart indicates the magnitude of which of the following?

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

Question 11

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following describes what contour lines represent on a 500 hPa chart?

A)lines of constant wind direction
B)lines of constant pressure
C)lines of constant density
D)lines of constant altitude

Question 12

MB
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In which side is there more air between 0 and 1.5 km altitude?

A)on the right
B)on the left

Question 13

MB
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Which of the following is the source of the expression "the force exerted on an object equals its mass times the acceleration produced"?

A)Buys-Ballot's law
B)Newton's second law of motion
C)the isobaric law
D)hydrostatic equilibrium

Question 14

North
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Which of the following air motions at pressure centres is correct?

A)Air sinks at both low-pressure centres and high-pressure centres.
B)Air rises at both low-pressure centres and high-pressure centres.
C)Air sinks at low-pressure centres and rises at high-pressure centres.
D)Air rises at low-pressure centres and sinks at high-pressure centres.

Question 15

In which of the following places is the pressure gradient force directed from high to low pressure?

A)the northern hemisphere
B)all places on Earth
C)the equator
D)the southern hemisphere

Question 16

Which of the following describes the air at the surface around a strengthening low-pressure area, and aloft, above the system?

A)Air diverges both at the surface and aloft.
B)Air converges both at the surface and aloft.
C)Air diverges at the surface and converges aloft.
D)Air converges at the surface and diverges aloft.

Question 17

North
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A stationary air parcel in the northern hemisphere begins to move in which of the following directions?

A)west
B)north
C)south
D)east

Question 18

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following corresponds to low pressures observed on a constant height chart?

A)low heights on a constant pressure chart
B)low pressures on a constant pressure chart
C)high heights on a constant pressure chart
D)high pressures on a constant high chart

Question 19

To accurately monitor horizontal changes in air pressure, a correction for which of the following factors is most important for a mercury barometer?

A)temperature
B)altitude
C)gravity
D)density

Question 20

Which of the following statements describes what a barograph does?

A)It draws isobars on a surface weather map.
B)It predicts pressures one or two days before they occur.
C)It measures and records atmospheric pressure.
D)It maintains the pressure in a room at a preset value.

Question 21

Which of the following describes pressure change in relation to direction?

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

Question 22

Which of the following statements best describes the gas law?

A)Temperature is proportional to density times pressure.
B)Pressure is proportional to density times temperature.
C)Density is proportional to pressure times temperature.
D)Temperature times pressure times density remains constant.

Question 23

Which of the following terms refers to lines connecting points of equal pressure?

A)isobars
B)isotherms
C)millibars
D)contours

Question 24

Which of the following gives the direction of the vertical pressure gradient force?

A)downward
B)constantly changing between upward and downward
C)never changing
D)upward

Question 25

Which of the following describes cyclonic flow regardless of the hemisphere?

A)It is a counterclockwise flow.
B)It is a clockwise wind flow.
C)It is circulation around a low-pressure centre.
D)It is circulation around a high-pressure centre.

Question 26

Which of the following expresses the gas law?

A)
B)
C)
D)

Question 27

MB
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Who invented the mercury barometer?

A)Aristotle
B)Newton
C)Coriolis
D)Torricelli

Question 28

The wind around a surface high-pressure centre in the northern hemisphere blows in which of the following directions?

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

Question 29

The weather condition in which hemisphere is depicted in the figure above?

A)northern hemisphere
B)southern hemisphere

Question 30

Which of the following instruments measures air pressure?

A)thermometer
B)radiometer
C)barometer
D)hygrometer

Question 31

Which of the following must balance the vertical pressure gradient force so that the atmosphere around the Earth does not rush off into space?

A)horizontal pressure gradient force
B)centripetal force
C)Coriolis force
D)gravity
Wind
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Question 32

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following describes an apparent force created by the Earth's rotation?

A)gravitational force
B)pressure gradient force
C)centripetal force
D)Coriolis force

Question 33

MB
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In which side is pressure decreasing most rapidly with increasing altitude?

A)on the right
B)on the left

Question 34

Which of the following conditions is constant on an isobaric surface?

A)altitude
B)temperature
C)density
D)pressure

Question 35

MB
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Which of the following describes the wind direction around a surface low-pressure centre in the southern hemisphere?

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

Question 36

In which of the following locations do winds blow slightly inward?

A)around surface low-pressure centres in the southern hemisphere
B)at the poles in the northern and southern hemispheres
C)around surface low-pressure centres in the northern hemisphere
D)around surface low-pressure centres in the northern and southern hemispheres

Question 37

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following describes the pressure at point A compared to the pressure at point B?

A)It is lower than the pressure at point B.
B)It is the same as the pressure at point B.
C)It is higher than the pressure at point B.

Question 38

Although the scale on an altimeter indicates altitude, an altimeter actually measures which of the following?

A)temperature
B)pressure
C)humidity
D)density

Question 39

Consider an airplane flying from standard temperature air into warmer than standard temperature air. Without making any correction, the altimeter in the warmer air would indicate which of the following conditions?

A)an altitude exactly the same as the airplane's altitude
B)an altitude correction factor to be used by the pilot
C)an altitude higher than the airplane's actual altitude
D)an altitude lower than the airplane's actual altitude

Question 40

Which force causes the wind to blow?

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

Question 41

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Suppose the winds aloft are geostrophic and blowing from the north. When isobars at the surface have the same orientation, from which of the following directions is the wind blowing?

A)southwest
B)northeast
C)southeast
D)northwest

Question 42

Which of the following forces can act to change the speed of the wind?

A)gravitational force
B)Coriolis force
C)pressure gradient force
D)potential force

Question 43

Referring to the figure below, at which of the following points are the pressures in the barometer equal? ​

A)points A and C
B)points C and D
C)points B and D
D)points A and D

Question 44

The surface pressures at the bases of warm and cold columns of air are equal. Which of the following describes the air pressure in the warm column of air compared to the air pressure in the cold column?

A)It increases with increasing height more slowly than in the cold column.
B)It increases with increasing height more rapidly than in the cold column.
C)It decreases with increasing height more rapidly than in the cold column.
D)It decreases with increasing height more slowly than in the cold column.

Question 45

Suppose a parcel of air has a given temperature, pressure, and density. Which of the following will happen to the air pressure inside the parcel if its size remains the same while its temperature increases?

A)Air pressure will decrease.
B)Air pressure will decrease to, but not lower than, 1000 hPa.
C)Air pressure will increase.
D)Air pressure will remain constant.

Question 46

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Which of the following describes where Point A lies?

A)in an upper-level trough
B)in an upper-level ridge

Question 47

Which of the following gives the name for a wind that blows at a constant speed parallel to curved isobars or contour lines?

A)geostrophic wind
B)cyclonic wind
C)gradient wind
D)convergent wind

Question 48

Which of the following is an accurate statement about the frictional force?

A)It accelerates winds near the surface.
B)It is zero at the equator.
C)It varies depending on the nature of the Earth's surface.
D)It is roughly the same up to an altitude of 5 km.

Question 49

Force
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A weather map for which hemisphere is indicated?

A)southern hemisphere
B)northern hemisphere

Question 50

For a given wind speed, at which of the following latitudes would the Coriolis force be weakest?

A)10
B)30
C)60
D)90

Question 51

Referring to Newton's second law of motion, which of the following determines the acceleration of the object?

A)force and mass
B)temperature and mass
C)force and temperature
D)mass and density

Question 52

Suppose a station at sea level measures an air pressure of 1030 hPa. Under standard conditions, which of the following values is the most likely air pressure at an elevation of 600 metres above this station?

A)970 hPa
B)1024 hPa
C)1030 hPa
D)1090 hPa

Question 53

Consider a surface low pressure area that moves from south to north directly east of your home in the northern hemisphere. Which of the following describes the resulting shift in wind direction?

A)from S to SE to E
B)from SE to E to SW
C)from N to NE to E
D)from NE to N to NW

Question 54

Consider the situation in which a wind blows at constant speed parallel to straight line isobars, and with the pressure gradient force (PGF) in balance with the Coriolis force. Which of the following is the name for this kind of wind?

A)geostrophic wind
B)gradient wind
C)cyclostrophic wind
D)meridional wind

Question 55

Typically, corrections need to be made for which of the following factors to obtain the station pressure?

A)temperature and gravity
B)temperature and time
C)operator error and temperature
D)temperature and altitude

Question 56

Surface
The solid line indicates the 850 mb pressure level, and points A and B are at the same altitude.
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Suppose the wind is blowing from the south directly above you at 3000 metres. Which of the following gives the direction at 3000 metres of the centre of lowest pressure?

A)north of you
B)south of you
C)east of you
D)west of you

Question 57

On an upper-level chart, which of the following is indicated by a ridge?

A)average heights
B)higher than average heights
C)a region with calm winds
D)lower than average heights

Question 58

Which of the following would happen to the atmospheric pressure at the ground if the Earth's gravitational force were to increase?

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

Question 59

Air Parcel
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Assuming that the figure refers to the northern hemisphere, in which of the following directions will the wind end up blowing?

A)east to west
B)counterclockwise around the high-pressure centre
C)west to east
D)clockwise around the high-pressure centre

Question 60

In the northern hemisphere, suppose you observe the upper-level winds blowing from the south. In which direction from you is the trough of low pressure?

A)west
B)east
C)north
D)south

Question 61

According to the gas law, which of the following expresses the relation between air pressure and air density when temperature remains constant?

A)
B)
C)
D)

Question 62

Which of the following describes why surface winds blow across the isobars at an angle?

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

Question 63

Which of the following describes the net force on air moving in a circle at constant speed?

A)overall null
B)inward toward the centre of rotation
C)outward from the centre of rotation
D)in the direction of wind motion

Question 64

Force
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The wind is blowing across the contour lines toward an area of which kind of pressure?

A)lower pressure
B)higher pressure

Question 65

Which of the following instruments has a dial similar to the one shown in the figure below? ​

A)microbarograph
B)Torricelli thermometer
C)aneroid barometer
D)tipping-bucket rain gauge

Question 66

Suppose a warm parcel of air at sea level is compared to a similar but very cold parcel of air at 5.5 km. Which of the following statements accurately compares the two parcels of air?

A)The parcel at sea level has higher pressure and higher density than the parcel at 5.5 km.
B)The parcel at sea level has lower pressure and lower density than the parcel at 5.5 km.
C)The parcel at sea level has lower pressure and higher density than the parcel at 5.5 km.
D)The parcel at sea level has higher pressure and lower density than the parcel at 5.5 km.

Question 67

Suppose the winds aloft are geostrophic and blowing from the north. In which of the following directions is low pressure located?

A)south
B)east
C)west
D)north

Question 68

Which of the following statements applies to the Coriolis force?

A)It cannot cause winds to change direction, but to increase or decrease in speed.
B)It causes winds to deflect to the left in the northern hemisphere.
C)It can cause winds to change direction, but not to increase or decrease in speed.
D)It causes the winds to deflect to the right in the southern hemisphere.

Question 69

Which of the following defines the ridges on a weather map?

A)dying hurricanes
B)elongated high-pressure areas
C)elongated low-pressure areas
D)mountains that stall the movement of storms

Question 70

North
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The wind in the northern hemisphere will eventually blow toward which of the following directions?

A)east
B)north
C)south
D)west

Question 71

A station at an altitude of 900 metres above sea level measures an air pressure of 930 hPa. Under normal conditions, which of the following values give the most realistic sea-level pressure for this station?

A)840 hPa
B)930 hPa
C)1020 hPa
D)1830 hPa

Question 72

Which of the following describes the relation on an upper-level chart between air temperature and pressure?

A)Warm air aloft is associated with constant pressure surfaces that are found at higher altitude than normal and lower than normal atmospheric pressure aloft.
B)Warm air aloft is associated with constant pressure surfaces that are found at lower altitude than normal and lower than normal atmospheric pressure aloft.lower; lower
C)Warm air aloft is associated with constant pressure surfaces that are found at higher altitude than normal and higher than normal atmospheric pressure aloft.
D)Warm air aloft is associated with constant pressure surfaces that are found at lower altitude than normal and higher than normal atmospheric pressure aloft.

Question 73

Wind
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Around which type of pressure area are the winds blowing around?

A)high pressure
B)low pressure

Question 74

Suppose at your home in the northern hemisphere the surface wind is blowing from the northwest. Which of the following directions relative to your home will have the region of lowest pressure?

A)south
B)east
C)north
D)west

Question 75

Which of the following describes the relation on an upper-level chart between air temperature and pressure?

A)Changing air temperature is normally associated with low pressure.
B)Constant air temperature is normally associated with low pressure.
C)Warm air is normally associated with high pressure.
D)Cold air is normally associated with high pressure.

Question 76

Which of the following gives the name for the force that causes a stationary parcel of air to begin to move horizontally?

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

Question 77

If the outside air temperature is 27°C and the air density is 1.2 kg/m3, which of the following is the outside air pressure?

A)32 hPa
B)93 hPa
C)930 hPa
D)1013 hPa

Question 78

Which of the following describes the state of the atmosphere when the upward-directed pressure gradient force is in balance with the downward pull of gravity?

A)unstable equilibrium
B)isobaric balance
C)hydrostatic equilibrium
D)geostrophic balance

Question 79

On a 500 hPa chart, which of the following represents horizontal changes in altitude that correspond to horizontal changes in pressure?

A)isobars
B)isotherms
C)contour lines
D)isotachs

Question 80

Air Parcel
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The pressure gradient force would cause the stationary parcel of air to begin to move in which of the following directions?

A)outward
B)inward