Deck 7: Precipitation

Question 1

​An important factor in the production of rain by the collision-coalescence process is the number of ice crystals in the cloud.

Answer 1

False

Question 2

Generally, the smaller the pure water droplet, the lower the temperature at which it will freeze.

Answer 2

True

Question 3

A warm stratus cloud is typically less than 500 m thick and has slow upward air movement (generally less than 0.1 m/sec).​

Answer 3

True

Question 4

A problem with the tipping bucket rain gauge is that during each "tip" it loses some rainfall and, therefore, under measures rainfall amounts, especially during heavy downpours.​

Question 5

In calm air, a typical cloud droplet falls over 600 times faster than a typical raindrop.​

Question 6

Very small cloud droplets of pure water can evaporate even when the relative humidity is 100 percent.

Question 7

​The Doppler radar has the capacity to measure the speed at which falling rain is moving horizontally toward or away from the radar antenna. Falling rain moves with the wind. Consequently, Doppler radar allows scientists to peer into a tornado-generating thunderstorm and observe its wind.

Question 8

A fluffy covering of snow protects sensitive plants and their root systems from damaging low temperatures.​

Question 9

After a rainstorm, visibility typically deteriorates.​

Question 10

​Bacteria in decaying plant leaf material can act as ice nuclei.

Question 11

A single rain gauge on top of a building cannot represent the total precipitation for any particular region.​

Question 12

​In a cloud over land, where the air temperature is -10 $\degree$ C, we would find many more cloud droplets than ice crystals.

Question 13

Generally, the concentration of nuclei is less over the oceans than over land.​

Question 14

​During cloud seeding, dry ice is much easier to handle than silver iodide, because it can be supplied to the cloud from burners located either on the ground or on the wing of a small aircraft.

Question 15

When the temperature in a cloud is -30°C, larger cloud droplets are more likely to freeze than smaller cloud droplets.

Question 16

Large, heavy snowflakes are associated with moist air and temperatures well below freezing.

Question 17

Large cloud droplets fall faster than small cloud droplets because gravity acts more strongly on larger droplets.

Question 18

​With a Doppler radar smaller targets require detection by longer wavelengths.

Question 19

Modern satellites are equipped with very sensitive radars that are able to peer into a cloud and provide a vertical view of its tiny cloud droplets and ice particles, as well as precipitation.​

Question 20

​In a cloud composed of water droplets and ice crystals, the saturation vapor pressure is greater over the droplets than over the ice.

Question 21

Which cloud type below will only produce precipitation by the collision-coalescence process?​

A) ​a thick, cold nimbostratus cloud
B) ​a thick, warm cumulus cloud
C) ​a thick, cold cumulus cloud
D) ​a thick, supercooled cumulonimbus cloud with abundant nuclei
E) ​a supercooled cumulus congestus cloud

Question 22

Condensation onto hygroscopic nuclei is possible at relative humidities less than 100 percent due to the​

A) ​curvature effect.
B) ​electrical charge on these nuclei.
C) ​solute effect.
D) ​crystalline structure of these nuclei.
E) ​size of the nuclei.

Question 23

If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ____ and had ____ updrafts.​

A) ​thick; weak
B) ​thick; strong
C) ​thin; weak
D) ​thin; strong
E) ​thin; no

Question 24

If rain falls on one side of a street and not on the other side, the rain most likely fell from a ____ cloud.​

A) ​nimbostratus
B) ​stratus
C) ​cumulonimbus
D) ​altostratus
E) ​altocumulus

Question 25

The growth of a precipitation particle by the collision of an ice crystal (or snowflake) with a supercooled liquid droplet is called​

A) ​accretion.
B) ​spontaneous nucleation.
C) ​condensation.
D) ​deposition.
E) ​collision.

Question 26

Fallstreaks most often form with​

A) ​nimbostratus clouds.
B) ​cumulonimbus clouds.
C) ​stratus clouds.
D) ​altostratus clouds.
E) ​cirrus clouds.

Question 27

What are the two main substances used in cloud seeding?​

A) ​lead iodide and dry ice
B) ​silver iodide and lead iodide
C) ​ice crystals and flood powder
D) ​dry ice and sea salt
E) ​silver iodide and dry ice

Question 28

The region of a cloud where only ice particles exist is called​

A) ​iced.
B) ​coated.
C) ​graupled.
D) ​nucleated.
E) ​glaciated.

Question 29

Cloud seeding using silver iodide only works in​

A) ​cold clouds composed entirely of ice crystals.
B) ​warm clouds composed entirely of water droplets.
C) ​cold clouds with a low ratio of ice crystals to water droplets.
D) ​clouds with more ice crystals than supercooled droplets.
E) ​clouds that can produce precipitation.

Question 30

Rain which falls from a cloud but evaporates before reaching the ground is referred to as​

A) ​sleet.
B) ​virga.
C) ​graupel.
D) ​dry rain.
E) ​drizzle.

Question 31

​Contact freezing is

A) ​the freezing of supercooled droplets by contact with a nucleus.
B) ​the sticking together of ice crystals to make a snowflake.
C) ​the joining of many nuclei to form an ice nucleus.
D) ​the freezing of supercooled droplets when they come into contact with a supercooled surface.
E) ​the sticking together of any type of nucleus.

Question 32

Which cloud would most likely produce drizzle?​

A) ​stratus
B) ​cumulus
C) ​cumulus congestus
D) ​cirrostratus
E) ​cumulonimbus

Question 33

A supercooled cloud droplet is​

A) ​an ice crystal surrounded by air warmer than 0°C (32°F).
B) ​a liquid droplet that is cooler than the air around it.
C) ​a liquid droplets observed at temperatures below 0°C (32°F).
D) ​a water droplet that has had all its latent heat removed.
E) ​another term for ice crystal.

Question 34

Which statement below best describes the curvature effect?​

A) ​large cloud droplets fall faster than small droplets.
B) ​small droplets evaporate more quickly than large droplets.
C) ​small droplets collide and coalesce more easily than larger droplets.
D) ​it explains the six-sided shape of ice crystals.
E) ​it explains the shape of rain drops.

Question 35

Which below best describes the solute effect?​

A) ​keeps water droplets from freezing at temperatures below 32°F
B) ​removal of pollutants from the atmosphere by cloud droplets
C) ​water droplets dissolve hygroscopic nuclei and condensation can occur at relative humidities less than 100 percent
D) ​evaporation of cloud droplets and growing of ice crystals in a cold cloud
E) ​condensation occurs at relative humidities of 100 percent

Question 36

The most common ice crystal shape is​

A) ​graupel.
B) ​dendrite.
C) ​rime.
D) ​virga.
E) ​a pentagon.

Question 37

For sub-freezing temperatures, the saturation vapor pressure just above a liquid water surface is ____ the saturation vapor pressure above an ice surface.​

A) ​greater than
B) ​the same as
C) ​less than
D) ​10% less than
E) ​50% less than

Question 38

​Fallstreaks usually ____ before reaching the ground.

A) ​evaporate
B) ​condense
C) ​sublimate
D) ​deposit
E) ​perspirate

Question 39

Large raindrops fall ____ smaller raindrops, and have ____ terminal velocity than/as small raindrops.​

A) ​faster than; a lesser
B) ​faster than; a greater
C) ​slower than; a lesser
D) ​slower than;, a greater
E) ​at the same rate as; the same

Question 40

During the ice crystal process of rain formation,​

A) ​only ice crystals are 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 -40°C (-40°F) or below.
D) ​the cloud must be a cumuliform cloud.
E) ​the surface temperature must be below freezing.

Question 41

A typical raindrop is about ____ than a typical cloud droplet.​

A) ​one thousand times smaller
B) ​one thousand times larger
C) ​one hundred times smaller
D) ​one hundred times larger
E) ​ten times larger

Question 42

After a snowstorm, the newspaper reports that Buffalo, New York, received 1.50 inches of precipitation. If we assume an average water equivalent ratio for this snowstorm, then Buffalo received about ____ inches of snow.​

A) ​3
B) ​1.5
C) ​10
D) ​9
E) ​15

Question 43

Which is the correct association?​

A) ​snow grains - hail
B) ​ground blizzard - graupel
C) ​snow squall - intense snow shower
D) ​sleet - glaze
E) ​freezing rain - hail

Question 44

Radar gathers information about precipitation in clouds by measuring the​

A) ​energy emitted by the precipitation particles.
B) ​absorption characteristics of falling precipitation.
C) ​amount of energy reflected back to a transmitter.
D) ​amount of sunlight scattered off the precipitation.
E) ​amount of solar energy passing through the cloud.

Question 45

The primary method used in preventing the growth of large, destructive hailstones is to inject a thunderstorm with large quantities of​

A) ​silver iodide.
B) ​ice crystals.
C) ​dry ice.
D) ​hydrophobic nuclei.
E) ​hailstone embryos.

Question 46

If a city were to receive 1/2 inch of rain in the morning and then 5 inches of snow that afternoon, about how much precipitation would the weather service report for that day?​

A) ​5 1/2 inches
B) ​1/2 inch
C) ​1 inch
D) ​10 inches
E) ​2 1/2 inches

Question 47

The idea in cloud seeding is to first find clouds that have too low a ratio of ice crystals to droplets and then to add enough artificial ice nuclei so that the ratio of crystals to droplets is about ____.​

A) ​1:100
B) ​1:1,000
C) ​1:10,000
D) ​1:100,000
E) ​1:1,000,000

Question 48

A Doppler radar is used to detect ____ and to measure ____.​

A) ​cloud droplets; nucleus types
B) ​storm systems; wind speed
C) ​snow covers; snow cover thickness
D) ​precipitation type; cloud coverage
E) ​areas of precipitation; rainfall intensity

Question 49

The Doppler radar uses the principle called Doppler ____ to measure the speed at which falling rain is moving horizontally toward or away from the radar antenna.​

A) ​signal
B) ​radiance
C) ​acceleration
D) ​speedometer
E) ​shift

Question 50

Satellites measure rainfall from space using which instrument?​

A) ​radar
B) ​tipping-bucket rain gauge
C) ​ceiliometer
D) ​weighing-type rain gauge
E) ​standard rain gauge

Question 51

In the winter you read in the newspaper that a large section of the Midwest is without power due to downed power lines. Which form of precipitation would most likely produce this situation?​

A) ​snow
B) ​hail
C) ​freezing rain
D) ​sleet
E) ​rain

Question 52

The lightest form of rain is​

A) ​shower.
B) ​cloudburst.
C) ​virga.
D) ​drizzle.
E) ​fallstreak.

Question 53

Some of the first experiments in cloud seeding were conducted by Vincent Schaefer and Irving Langmuir during the late 1940s. To seed a cloud, they dropped crushed pellets of ____ from a plane.​

A) ​silver iodide
B) ​silver iodine
C) ​lead iodide
D) ​cupric sulfide
E) ​dry ice

Question 54

The main difference between a cloud drop and a raindrop is its​

A) ​color.
B) ​size.
C) ​shape.
D) ​nucleus type.
E) ​associated precipitation type.

Question 55

Which of the following might be mistaken for hail?​

A) ​virga
B) ​graupel
C) ​dendrite
D) ​supercooled droplet
E) ​ice crystal

Question 56

An amount of precipitation measured to be less than one-hundredth of an inch (0.25 mm) is called​

A) ​a trace.
B) ​drizzle.
C) ​light rain.
D) ​mist.
E) ​fog.

Question 57

Which is the correct association?​

A) ​snow grains - ice pellet
B) ​ground blizzard - graupel
C) ​snow squall - intense snow shower
D) ​sleet - glaze
E) ​freezing rain - hail

Question 58

In a typical advancing winter storm, which of the following sequences of precipitation types is most likely to occur?​

A) ​freezing rain, rain, snow, sleet
B) ​freezing rain, rain, sleet, snow
C) ​rain, freezing rain, snow, sleet
D) ​rain, sleet, freezing rain, snow
E) ​rain, freezing rain, sleet, snow

Question 59

Precipitation with the greatest size (diameter) is​

A) ​the snow pellet.
B) ​the snow grain.
C) ​a hailstone.
D) ​sleet.
E) ​a rain drop.

Question 60

On average, the water equivalent of 10 inches of snow is about ____ inch(es) of water.​

A) ​0.5
B) ​1
C) ​2
D) ​2.5
E) ​5

Question 61

​The speed of falling cloud droplet increases until the air resistance

A) ​is greater than gravity.
B) ​is greater than the droplets inertia.
C) ​is less than gravity.
D) ​equals the pull of gravity.
E) ​is less than the droplets momentum.

Question 62

Heavy showers usually fall from ____________________clouds, whereas steady precipitation normally falls from ____________________clouds.​

Question 63

A standard rain gauge consists of a funnel-shaped collector attached to a long measuring tube. The cross-sectional area of the collector is ____ times that of the tube. Hence, rain falling into the collector is amplified ____ in the tube, permitting measurements of great precision.​

A) ​2; twofold
B) ​4; fourfold
C) ​6; sixfold
D) ​8; eightfold
E) ​10; tenfold

Question 64

Radar stands for ____________________.​

Question 65

Raindrops that reach Earth's surface are seldom larger than​

A) ​2 mm
B) ​3 mm
C) ​5 mm
D) ​8 mm
E) ​10 mm

Question 66

Remote recording of precipitation can be made with a(n) ____________________rain gauge. With this gauge, precipitation is caught in a cylinder and accumulates in a bucket. The bucket sits on a sensitive weighing platform. Special gears translate the accumulated weight of rain or snow into millimeters or inches of precipitation.​

Question 67

An instrument that can collect and measure rainfall is called a(n) ____________________.​

Question 68

Snow accumulation rates may be measured at a single site by using a(n) ____________________, a small wooden platform resting near the ground that is cleared off after each measurement.​

Question 69

A common term used for saturation vapor pressure when referring to cloud droplets is ____________________ vapor pressure.​

Question 70

Dry ice has a temperature of​

A) ​-28 degrees Celsius (-18 degrees Fahrenheit).
B) ​-48 degrees Celsius (-54 degrees Fahrenheit).
C) ​-58 degrees Celsius (-72 degrees Fahrenheit).
D) ​-78 degrees Celsius (-108 degrees Fahrenheit).
E) ​-98 degrees Celsius (-144 degrees Fahrenheit).

Question 71

The Precipitation Radar, located onboard the TRMM (Tropical Rainfall Measuring Mission) satellite, is able to measure rainfall intensity in previously inaccessible regions of the tropics and subtropics, and is capable of detecting rainfall rates down to about ____ per hour.​

A) ​0.1 mm (0.004 in.)
B) ​0.3 mm (0.01 in.)
C) ​0.5 mm (0.02 in.)
D) ​0.7 mm (0.03 in.)
E) ​0.9 mm (0.04 in.)

Question 72

Suppose a thick nimbostratus cloud contains ice crystals and cloud droplets all about the same size. The precipitation process most important in producing rain from this cloud is called the ____________________ process.​

Question 73

In a standard rain gauge ____ inches of water in the tube would be measured as 1 inch of rainfall.​

A) ​2.5
B) ​5
C) ​7.5
D) ​10
E) ​12.5

Question 74

Radar images typically are displayed using various colors to denote the intensity of precipitation, with ____ representing the lightest precipitation and ____ representing the heaviest precipitation.​

A) ​white; black
B) ​light grey; dark grey
C) ​orange; green
D) ​dark blue or purple; yellow or bright green
E) ​light blue or green; orange or red

Question 75

In dry powdery snow, the water equivalent ratio may be as high as​

A) ​15:1.
B) ​20:1.
C) ​25:1.
D) ​30:1.
E) ​35:1.

Question 76

The radar unit consists of a transmitter that sends out short, powerful ____ pulses.​

A) ​microwave
B) ​ultraviolet light
C) ​transmitted light
D) ​reflected light
E) ​X-ray

Question 77

Typical cloud droplets seldom reach the ground as rain because they ____________________ before reaching the ground.​

Question 78

Atmospheric conditions that produce sleet differ from those that produce hail because for sleet to form, surface temperatures must be ____________________ freezing, whereas surface temperatures are typically well ____________________ freezing during hailstorms.​

Question 79

When a Doppler radar has collected data, the returning signal is amplified and displayed on a screen, producing an image, also called a(n)____________________, from the target.​

Question 80

In clouds with tops warmer than -15 degrees Celsius (5 degrees Fahrenheit), the ____ can play a significant role in producing precipitation.​

A) ​solute effect
B) ​condensation
C) ​curvature effect
D) ​evaporation
E) ​collision-coalescence process