Geo 7

What instrument do we use to measure atmospheric pressure?

Barometer

An altimeter is often just an aneroid barometer that has been calibrated to indicate altitude.

True

Clouds, fogs, and precipitation are more likely to form where prevailing winds are upslope than where the winds are downslope.

True

Pressure ALWAYS changes with height.

True

The Coriolis force acts at right angles to the wind, only influencing wind direction and never wind speed.

True

A surface low pressure center is generally associated with ____ on an upper-air isobaric chart.

a trough

When the upward-directed pressure gradient force is in balance with the downward pull of gravity, the atmosphere is in ____.

hydrostatic equilibrium

The most practical location for building a wind turbine would be ____.

in a region of moderate, steady winds

If Earth's gravitational force were to increase, atmospheric pressure at the ground would ____.

increase

Buys-Ballot's law states that, "In the Northern Hemisphere if you stand with your back to the surface wind, then turn clockwise about 30 degrees, lower pressure will be ______________."

to your left

https://d2l.msu.edu/d2l/common/viewFile.d2lfile/Database/MjAyMzk2Mw/850MillibarLevel.gif?ou=1083413 The air at point A is ____________________ the air at point B.

warmer than

If directly above you at 10,000 feet the wind is blowing from the south, then it is a good bet that at 10,000 feet, the center of lowest pressure is ______ of you, while the center of highest pressure is ______ of you.

west; east

An object is falling at constant speed. The net force is ____.

zero

The net force acting on air that is blowing parallel to straight contours at constant speed is ____.

zero

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

1,020 millibars

What is the standard sea-level pressure in millibars?

1013 millibars

Standard sea-level pressure is ____ millibars.

1013.25

If you went up 1500 meters and your new pressure is 870 millibars, what is the pressure at the surface?

1020 millibars

Which of the following is not equivalent to standard sea-level pressure? 1013.25 hectopascal 1013.25 millibars 29.92 torr 101325 pascal 29.92 inches of mercury

29.92 torr

If you went up 500 meters, and your pressure initially was 1020 millibars, what would be your new pressure?

970 millibars

Surface weather maps have what kind of pressure readings for areas?

Altitude-adjusted

Which of the following is not a horizontal force on air motion?

Centrifugal Force

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

Coriolis

What causes horizontal pressure changes?

Different rates of change in terms of temperature

A wind profiler obtains wind information using a(n) ____.

Doppler radar

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

F

Atmospheric (air) pressure is the pressure exerted by the mass of air below a region.

False

Coriolis force affects wind speed, not direction.

False

Coriolis force influences wind speed and direction.

False

Friction results in slower wind speeds and changes wind direction.

False

Two parcels of air with the same volume and temperature will also always have the same pressure.

False

When the pressure gradient force and Coriolis force on wind are balanced out, but there is still wind, what is this called?

Geostrophic winds

Which of the statements below is incorrect concerning the pressure gradient force? It can cause the wind to speed up or slow down. It is non-existent at the equator. The pressure gradient force points from high to low pressure in the Southern Hemisphere. The pressure gradient force points from high to low pressure in the Northern Hemisphere.

It is non-existent at the equator.

Which of the following is not a reason for pressure to change in the horizontal axis?

Movement of tree limbs and grasses

Suppose a column of air has constant air temperature. What would happen if we force more air into the column?

The air would become more dense, and the surface air pressure would increase.

If you lived in the middle of large town and there were two weather stations for it (one at the West end of the town and one at the East end of town), which of the options below would result in the highest winds at your house?

West = 1020 millibars; East = 990 millibars

The winds aloft in the middle latitudes would not blow from the west if ____.

air over high latitudes became warmer than over the equator

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

altitude

A _______ barometer is the most commonly used type today and consists of a metal container and paper to record the atmospheric pressure.

aneroid

Winds blow slightly inward ____.

around surface low pressure centers in the Northern and Southern Hemispheres

The pressure gradient force is directed from higher pressure toward lower pressure ____.

at all places on Earth

In the vertical, the pressure gradient force points ____ and gravity points ____.

away from Earth; toward Earth

https://d2l.msu.edu/d2l/common/viewFile.d2lfile/Database/MjAyMzk2OQ/HighWithAirParcel.gif?ou=1083413 Assuming that the figure above is in the northern hemisphere, the wind will end up:

blowing in a clockwise direction.

A gradient wind blowing around the low-pressure center is constantly accelerating because it is constantly changing directions. This is called ____.

centripetal acceleration

Cyclonic flow means ____ in either the Northern or Southern Hemisphere.

circulation around a low pressure center

The wind around a surface low pressure center in the Southern Hemisphere blows ____ the center.

clockwise and inward toward

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

clockwise and outward from

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

converges; diverges

Which of the following forces cannot act to change the speed of the wind?

coriolis force

If upper-level divergence exceeds surface convergence, the air pressure at the center of the low will ____, and the isobars will become ____ tightly packed.

decrease; more

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.

decrease; more slowly

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 ____ of your home.

east

Suppose that the winds aloft in the Northern Hemisphere are geostrophic and blowing from the north. Low pressure is located to the ____.

east

Heating (but not cooling) columns of air can establish horizontal variations in atmospheric pressure aloft and at the surface.

false

Pressure gradient force (PGF) is a horizontal difference in atmospheric pressure, which causes air to move from low pressure to high pressure.

false

Pressure gradient force is caused by air moving from areas from low pressure to high pressure.

false

Sea level pressure at a location and the pressure at the surface of the same location are effectively the same.

false

Which combination produces the strongest Coriolis force?

fast winds and high latitude

Which of the following produces the strongest Coriolis force?

fast winds, high latitude

A ____ wind blows at a constant speed parallel to straight line isobars, with the pressure gradient force (PGF) and the Coriolis force in balance.

geostrophic

A wind that blows at a constant speed parallel to straight isobars or contour lines is called a _____________ wind.

geostrophic

A wind that blows at a constant speed parallel to curved isobars or contour lines is called a ____ wind.

gradient

Which force does not have a direct effect on horizontal wind motions?

gravitational force

Which of the following forces does not have a direct effect on horizontal wind motions? frictional force pressure gradient force coriolis force gravitational force

gravitational force

The atmosphere around Earth would rush off into space if the upward-directed pressure gradient force were not exactly balanced by ____.

gravity

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

high; low

A ridge on an upper-air isobaric chart indicates ____.

higher-than-average heights

The large red L's on a surface map represent centers of low pressure, also known as ____ storms.

mid-latitude cyclonic

Atmospheric pressure changes ____.

more rapidly in the vertical direction than in the horizontal

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 ____.

northwest

On an upper-air chart, the wind aloft tends to blow ____.

parallel to the isobars or contours

The scale on an altimeter indicates altitude, but an altimeter actually measures ____.

pressure

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

pressure gradient

Once the wind starts to blow, the Coriolis force causes it to bend to the _____ of its intended path in the Northern Hemisphere and to the _____ of its intended path in the Southern Hemisphere.

right; left

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

rising; sinking

The magnitude of the frictional force (FF) depends upon the ______ of the air parcel and the ______ of the earth's surface.

speed; roughness

A ____ pressure usually indicates clearing weather or fair weather.

steadily rising

To obtain the station pressure, you must normally make corrections for ____.

temperature and gravity

The Coriolis effect is a force on wind that comes from:

the Earth's rotation.

An aneroid barometer measures pressure by having a metal container squeezed by the ambient atmospheric temperature.

true

Upper-level winds blow from west to east in both the Northern and Southern Hemispheres.

true