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Relative humidity changes with

water vapor and temperature

Which of the following would cause relative humidity to decrease?
a. cooling the air
b. warming the air
c. increasing the air pressure
d. changing the wind direction

warming of the air

At what time of day is the relative humidity normally at a minimum?

when the air temperature is highest

If the air temperature remains constant, evaporating water into the air will ______ the dew point and ______ the relative humidity.

increase, increase

The temperature to which air must be cooled in order to become saturated is the

dew point temperature

As the difference between the air temperature and the dew point increases, the relative humidity

decreases

This instrument uses wet-bulb and dry-bulb temperatures to obtain relative humidity.

sling psychrometer

A large difference between the dry- and wet-bulb readings on a psychrometer indicates

dry conditions

Dew is most likely to form on
a.clear, calm nights.
b.cloudy, calm nights.
c.clear, windy nights.
d.cloudy, windy nights.
e.rainy nights.

clear, calm nights

The cooling of the ground to produce dew is mainly the result of

radiational cooling

Radiation fog forms best on a
a. clear winter night with no breeze.
b. cloudy winter night with a strong breeze.
c. clear summer night with a strong breeze.
d. cloudy summer night with a slight breeze.
e. cloudy winter night with a slight breeze.

clear winter night with no breeze

The fog that forms along the Pacific coastline of North America is mainly this type.

advection fog

When fog lifts above the ground it normally forms this gray sheetlike cloud.

stratus

Which association below is not correct?
a. cirrocumulus - high cloud
b. cumulus - cloud of vertical extent
c. altostratus - high cloud
d. stratus - lowcloud

altostratus - high cloud

An anvil-shaped top is most often associated with
a.cumulonimbus.
b.Stratocumulus
c.altocumulus.
d.Nimbostratus

cumulonimbus

Cirrus clouds are composed primarily of

ice particles

The cloud with the greatest vertical growth is
a.stratocumulus.
b.cumulus.
c.cumulonimbus.
d.Cirrocumulus.
e.altocumulus.

cumulonimbus

A halo around the moon means that
a.cirrostratus clouds are present.
b.the clouds overhead are low clouds.
c.rain is falling from the clouds overhead.
d.the clouds are composed of water droplets.

cirrostratus clouds are present

Light or moderate-but-steady precipitation is most often associated with ______ clouds.
a.
nimbostratus
b.
Cirrostratus
c.
Cirrocumulus
d.
cumulonimbus

nimbostratus

Which of the following clouds generally forms at the lowest altitude?

a.
Cirrostratus
b.
stratocumulus
c.
Altocumulus
d.
Cirrus

stratocumulus

The rate at which the actual air temperature changes with increasing height above the surface is referred to as the

environmental lapse rate

If an air parcel is given a small push upward and it falls back to its original position, the atmosphere is said to be

stable

If an air parcel is given a small push upward and it continues to move upward on its own accord, the atmosphere is said to be

unstable

The rate at which the temperature changes inside a rising (or descending) parcel of saturated air is called

moist adiabatic lapse rate

The dry adiabatic rate is the rate at which
a.
an air parcel rises.
b.
temperature changes in a rising or descending parcel of unsaturated air.
c.
volume changes when a parcel expands or is compressed.
d.
latent heat energy is released in a rising air parcel.

temperature changes in a rising or descending parcel of unsaturated air

A knowledge of air stability is important because

it determines the vertical motion of air

Which condition below would make a layer of air more unstable?
a. an increase in wind speed
b. lifting the entire air layer
c. cooling the upper part of the layer
d. all of the above

all of the above

Which set of conditions, working together, will make the atmosphere the most stable?
Which set of conditions, working together, will make the atmosphere the most sta-ble?
a.
cool the surface and warm the air aloft
b.
cool the surface and cool the air aloft
c.
warm the surface and cool the air aloft
d.
warm the surface and warm the air aloft

cool the surface and warm the air aloft

What two sets of conditions, working together, will make the atmosphere the most unstable?
a.
cool the surface and warm the air aloft
b.
cool the surface and cool the air aloft
c.
warm the surface and cool the air aloft
d.
warm the surface and warm the air aloft

warm the surface and cool the air aloft

Which cloud type below would most likely form in an unstable atmosphere?
a.
cumulonimbus
b.
Stratus
c.
Cirrostratus
d.
Nimbostratus
e.
Altostratus

cumulonimbus

The vertical motion of air caused by sun heating the ground is called

convection

An example of orographic clouds would be
a.
clouds forming over a warm ocean current.
b.
clouds forming on the windward slope of a mountain.
c.
clouds forming behind a jet airplane.
d.
clouds formed by surface heating.

clouds forming on the windward slope of a mountain

The name commonly used to describe the drier region observed on the downwind (leeward) side of a mountain range is

rain shadow

During the ice crystal process of rain formation (Bergeron Process)
a. only ice crystals need be present in a cloud.
b. ice crystals grow larger at the expense of the surrounding liquid cloud droplets.
c. the temperature in the cloud must be -40o C (-40o F) or below.
d. the cloud must be a cumuliform cloud.

ice crystals grow larger at the expense of the surrounding liquid cloud droplets

Which cloud type below will only produce precipitation by the collision-coalescence process?
a. a thick, warm (32F+) nimbostratus cloud
b. a thick, warm cumulus cloud
c. a thick, cold (32F-) cumulus cloud
d. a thick, supercooled cumulonimbus cloud with abundant nuclei
e. a supercooled cumulus congestus cloud

a thick, warm cumulus cloud

A raindrop which freezes before reaching the ground is called

sleet

Sea-level pressure values generally fall in the range

950 to 1050 mb

Which of the following instruments measures pressure?
a.
barometer
b.
Thermometer
c.
Radiometer
d.
hygrometer
e.
densitometer

barometer

A station at an altitude of 900 m (about 3000 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
c. 1020 mb
b. 930 mb
d. 1830 mb

1020 mb

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

temperature

A _______ usually indicates clearing weather or fair weather.

steadily rising pressure

Lines connecting points of equal pressure are called

isobars

The _______ is an apparent force created by the earth's rotation.

Coriolis force

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

pressure gradient force

Surface winds blow across the isobars at an angle due to

the frictional force

Cyclonic flow means _______ in either the Northern or Southern Hemisphere.
a.
clockwise wind flow
b.
counterclockwise flow
c.
circulation around a low pressure center
d.
circulation around a high pressure center

circulation around a low pressure center

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

rising, sinking

The surface air around a strengthening low pressure area normally ______ , while, above the system, the air normally_______

converges, diverges

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.

clockwise and outward from the center

An instrument used to measure wind speed is called a(an)

anemometer

The great Mississippi River flood - documented in the NOVA video "Flood" - occurred in what year?

1993

It is possible to have more than one "hundred year flood" in a hundred years.

True

People have contributed to the rising cost of floods along the Mississippi River by building their homes in the Mississippi River flood plain.

True

The Mississippi River flood was caused by a shift in the normal path of the Jet Stream which caused almost continuous precipitation over the Mississippi River watershed.

True

The great Mississippi River flood was the worst flood in recorded American history.

True

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