215 terms

Meteorology Today Test #2 Review

Questions from the Textbook Meterorology Today, 9th edition by C. Donald Ahrens
The temperature at which saturation occurs
dew point
Condensed water vapor that forms on surfaces such as twigs, leaves, and blades of grass as the temperature drops.
The dew becomes ____ dew when the air temperature drops below freezing.
frozen dew
Averaged for an entire year in middle latitudes, dew yields a blanket of water between ____ thick.
12-50mm thick
On clear, calm nights, objects near the earth's surface cool rapidly by emitting _____ _____
infrared radiation
Dew is more likely to form on nights that are ____ and _____ than on nights that are _____ and _____.
clear and calm, cloudy and windy
Cloudy, windy weather that inhibits rapid cooling near the ground and the forming of _____ often signifies the approach of a _____ storm system.
dew, rain-producing
The name for dew-point when the temperature drops below freezing.
When water vapor changes directly into ice.
When air cools to the dew point, the relative humidity becomes _____% and the air is saturated. Continued cooling condenses some of the vapor into tiny ____ _____
100, cloud droplets
A volume of air about the size of an index finger contains between _____ and ____ particles.
1000 and 150,000
Particles which serve as surfaces on which water vapor can condense.
condensation nuclei
British physicist who discovered that water vapor condenses on nuclei.
John Aitken
Particles ranging from 0.2 to 1um
large nuclei
Particles with a range exceeding 1um
giant nuclei
Condensation nuclei most favorable for producing clouds have a radii of ____um
0.1 and are called cloud condensation nuclei
Provide the the major source of cloud condensation nuclei in the marine atmosphere.
Means "water-seeking". eg: salt
Means "water-repelling". eg: oils, gasoline, waxes
Haze, fog, and clouds will form at relative humidity near or below ____% due to the mixture of particles in the air.
A layer of dust or salt particles suspended above a region.
As humidity increases from about 60% to 80%, the scattering effect of wet haze increases a factor of nearly ____.
The thin white veil across the horizon is due to ____
When the visibility lowers to less than 1km, and the air is wet with countless millions of tiny floating water droplets, the wet haze becomes a cloud resting near the ground, which we call _____
Fog that forms over cities is _____ than fog that forms over the oceans with eh same water content due to the greater number of nuclei.
Fog that forms in polluted air can turn acidic as the tiny liquid droplets combine with gaseous impurities, such as oxides of sulfur and nitrogen to form _____
Acid fog
Two ways in which fog forms:
1. by cooling- air is cooled below its saturation point (dew point)
2. by evaporation and mixing- water vapor is added to the air by evaporation, and the moist air mixes with relatively dry air
_____ and _____ are the primary means for cooling the nighttime air near the ground.
radiation and conduction
Fog produced by the earth's radiational cooling is called ______ fog
radiation fog (ground fog)
Occurs when warm, moist air moves over a cold surface and the air cools to below its dew point
Advection fog
Fog that forms as relatively wars moist air moves over a colder surface that cooled mainly by radiational cooling.
Advection-radiation fog
Fog that forms as moist air flows up along an elevated plain, hill or mountain.
upslope fog
Fog produced when sufficient water vapor is added to the air by evaporation, and the moist air mixes with relatively drier air.
The two common types are _____ fog, which forms when cold air moves over warm water, and ______ fog, which forms as warm raindrops evaporate in a cool air mass.
Evaporation (mixing fog)
steam, frontal
A cloud resting on the ground composed of water droplets, ice crystals, or a combination of both.
A visible aggregate of tiny water droplets or ice crystals suspended in the air.
a cloud
There are ___ basic types of clouds.
Latin to English:
layer - sheet like
heap - puffy
curl of hair - wispy
violent rain - rain cloud
high cirriform clouds are composed almost entirely of ____ ____
ice crystals
Most common high clouds which are thin, wispy clouds blown by high winds into long streamers called mares' tails.
cirrus (Ci)
Thin, sheetlike, high clouds that often cover the entire sky. So thin that the sun and moon can be clearly seen through them. The ice crystals in these clouds end the light passing through them and will often produce a halo.
Cirrostratus (Cs)
Clouds seen less frequently than cirrus, appear as small, rounded, white puffs that may occur individually or in long rows
Usually cover small portion of the sky, small ripples resemble fish scales, mackeral sky
Cirrocumulus (Cc)
Gray or blue-gray cloud composed of ice crystals and water droplets. Often cover the entire sky across an area that extends over many hundreds of square kilometers.
Altostratus (As)
Middle clouds composed mostly of water droplets and are rarely more than 1km thick. They appear as gray, puffy masses, sometimes rolled out in parallel waves or bands. Usually one part is darker than another.
Altocumulus (Ac)
A dark gray, "wet"-looking cloudy layer associated with more or less continuously falling rain or snow.
nimbostratus (Ns)
Low lumpy clouds that appear in rows, in patches, or as rounded masses with blue sky visible between the individual cloud elements.
stratocumulus (Sc)
Puffy cloud that takes on a variety of shapes, but most often it looks like a piece of floating cotton with sharp outlines and a flat base.
cumulus (Cu)
If a cumulus congestus continues to grow vertically, it develops into a giant _____
cumulonimbus (Cb)
A uniform grayish cloud that often covers the entire sky. Resembles a fog that does not reach the ground.
Stratus (St)
Moist air crossing a mountain barrier often forms into waves. The clouds that form in the wave rest usually have a lends shape and are therefore, called ____ _____
lenticular clouds
When a cloud forms over and extends downwind of an isolated mountain peak.
banner cloud
Cap cloud. Resembles a silken scarf capping the top of a sprouting cumulus cloud.
Form in sinking air. Appear as baglike sacs that hang beneath the clouds and resemble a cow's udder.
Mammatus clouds
Jet aircraft flying at high altitudes often produce a cirrus-like trail of condensed water vapor called a condensation trail or a ____
Seen above the troposphere. Soft pearly looking clouds.
nacreous clouds
Wavy bluish-white clouds, so thin that stars shine brightly through them, may sometimes been seen in the upper mesosphere, at altitudes above _____km
noctilucent clouds
Fog formed as moist, stable air flows upward over a topographic barrier
upslope fog
The amount of time the air temperature during the winter must remain below a certain value so that fruit and nut trees will grow properly during the spring and summer.
winter chilling
Also called could condensation nuclei. Tiny particles upon whose surfaces condensation of water vapor begins in the atmosphere. Small nuclei less than 0.2um in radius are called Atiken nuclei; those with a radii between 0.2 and 1 um are large nuclei, while giant nuclei have a nuclei larger than 1um.
Condensation nuclei
Evaporation (mixing) fog- fog produced when sufficient water vapor is added to the air by evaporation, and the moist air mixes with relatively drier air. The two common types are steam fog, which forms when cold air moves over warm water, and frontal fog, which forms as warm raindrops evaporate in a cool air mass.
Steam fog
Occurs when warm, moist air moves over a cold surface and the air cools to below its dew point
Advection fog
(also called radiation frost) refers to the white ice crystals, loosely deposited on the ground or exposed objects, that form on cold clear nights when heat losses into the open skies cause objects to become colder than the surrounding air.
Hoar frost
Fog that most commonly forms on clear nights, with light or calm winds
Radiation fog
The most abundant gases in the earth's atmosphere by volume are
carbon dioxide and nitrogen
What is a variable gas in the earth's atmosphere?
water vapor
In the atmosphere, tiny solid or liquid suspended particles of various composition are called:
What gas in the atmosphere is not considered a greenhouse gas?
The outpouring of gases from the earth's hot interior is called:
Name three units of pressure:
millibars, inHg, pascals
The temperature of the tropopause is much (colder/hotter) than the temperature at the earth's surface.
The instrument that measures temperature, pressure, and humidity at various altitudes int he atmpsphere:
The heat energy released when water vapor changes to a liquid is called:
latent heat of condensation
The change of state of ice into water vapor is known as:
The proper order from shortest to longest wavelength is:
ultraviolet, visible, infrared
If the average temperature of the sun increase, the wavelength of peak solar emission would:
shift to a shorter wavelength
An important reason for the large daily temperature range over deserts is:
there is little water vapor in the air to absorb and re-radiate infrared radiation
During an equinox:
days and nights are of equal length, sun is overhead the equator, earth is not tilted toward nor away from the sun
The maximum in daytime surface temperature typically occurs ____ the earth receives its most intense solar radiation.
Seasons are caused by:
the angle at which sunlight reaches the earth, the length of the daylight hours
Lines connecting points of equal temperature
Water changes form liquid to a vapor
This is used as an index for fuel consumption:
heating degree-days
composed of ice crystals, white and whispy, indicate fair weather
ususally cover small portion of the sky, small ripples resemble fish scales, mackeral sky,
thin sheet like clouds that cover the whole sky and form a halo around the sun
composed of water droplets; only one km thick; gray puffy masses; often in parallel bands;
gray or blue ice crystals that have watery sun
alto stratus
dark gray wet looking and continuously falling rain or snow, light or moderately steady precip
nimbo stratus
low lumpy clouds that appear in rows, patches, or rounded masses
uniform grayish clouds covers whole sky kind of like fog that doesnt touch ground
puffy cottonball like clouds
aka thunderheads, bring hail and lightning and thunder
fog that forms as moist air flows upward along an elevated surface
upslope fog
artic sea smoke and steam devils are a form of this type of fog
steam fog
a tiny liquid drop of dew that freezes when the air temp. drops below freezing
frozen dew
fog that most often forms as warm rain falls into a cold layer of surface air
frontal fog
the most common type of fog along the pacific coast of north america
advection fog
light shower of snow that falls intermittently from cumuliform clouds for a short duration
ragged looking clouds that drift rapidly with the wind often beneath a nimbrosrtatus cloud
least likely to produce precipitation that reaches the ground
evaporating precip that does not reach ground
lens shaped; formed my moist air; crossing mountains
lenticular clouds
cap cloud, form above a cumulonimbus cloud or cumulus congestus cloud b/c most winds are defected to top of cloud
pileus clouds
called cow udders, form on underside of cumulonimbus clouds or form in sinking air
formed when warm air rides up and over cold surface this is why we get foggy days after a big snow followed by warm temps
frontal fog
warm moist air moves inland from gulf air passes over cooler areas and air cools below dew point and spreads over a large region and common in central US
advection/radiation fog
polluted air with condensation nuclei and is a health danger
acid fog
The percent of water vapor in the air compared to that required for saturation.
relative humidity
The lowest temperature that can be attained by evaporating water into the air is the ____ ____
wet bulb
The temperature at which the air must be cooled for saturation to occur is called the ____ ____
dew point
On most days the relative humidity reaches its highest value when the air temperatures reaches its ____ value.
The circulation of water within the atmosphere is called the ____ cycle.
Instruments that measure humidity are called ____
When the air temperature increase, the saturation vapor pressure:
Which is the best indicator of the actual amount of water vapor in the air?
dew-point temperature
If the air temperature remain constant, evaporating water into the air will ____ the dew-point temperature and ____ the relative humidity.
increase, increase
Why in NA the Gulf Coast states are more humid in summer than the coastal areas of southern California?
the surface water temperature of the Gulf of Mexico is very warm
What two factors cause the relative humidity of air to change.
Change air's water vapor content. Change air temperature.
Dew, frost, and frozen dew form when objects on the surface cool below the air's ____ ____ temperature
dew point
____ ____ are important int he atmosphere because they serve as surfaces on which water vapor condenses.
Condensation nuclei
Fog can form as the air____, or as water evaporates and mixes with ____ air
cools, drier
____ not only photograph clouds, they provide scientists with a great deal of physical information about the earth and its atmosphere.
Another name for visible white frost.
These particles serve as surfaces on which water vapor may condense.
condensation nuclei
Fog that forms as moist air flows upward along an elevated surface.
upslope fog
Arctic sea smoke and "steam devils" are a form of this type of fog.
Steam fog
Fog that forms when cold air moves over something warm...like a hot tub in the winter.
Steam fog
A tiny liquid drop of dew that forms as rain falls into a cold layer of surface air.
frozen dew
A positive benefit of fog for fruit and nut trees
winter chilling
Fog that most often forms as warm rain falls into a cold layer of surface air
frontal fog
The most common type of fog along the Pacific coast of North America.
Advection fog
Beads of water that have condensed onto objects near the ground
Fog that most commonly forms on clear nights, with light or calm winds.
radiation fog
A "mackerel sky" describes this cloud
A low, lumpy cloud layer that appears in rows, patches, or rounded masses.
A towering cloud that has not fully developed into a thunderstorm
cumulus congestus
Hail is usually associated with this cloud type
The sun or moon are dimly visible or appear watery through this gray, sheetlike cloud
A halo around the sun or moon often identifies the presence of this cloud
Wispy, high clouds
Light or moderate but steady precipitation that covers a broad area is most often associated with this cloud
This cloud's elements (puffs) should be about the size of your thumbnail when your hand is extended to arm's length
Lightening and thunder are associated wit this cloud
A cloud o vertical development that resembles a small piece of floating cotton
A middle cloud that occasionally forms in parallel waves or bands
The cloud with the smallest elements or puffs as viewed from the surface
A low, uniform, grayish cloud, whose precipitation is most commonly drizzle.
This clouds elements (puffs) should be about the size of your fist when your hand is extended to arm's length
When fog lifts above the surface it forms this gray, sheetlike cloud
Cloud with the greatest vertical growth
Cirrus clouds are composed primarily of ____ ____
ice crystals
Fog that forms as relatively warm air moves over a colder surface is called _____ ____
Advection fog
The cooling of the ground to produce dew and frost is mainly the result of _____
Clouds that appear as baglike sacks hanging from beneath a cloud are called _____
Another name for "water-seeking" condensation nuclei
Another name for a "luminous night cloud" is ____ ____
noctilucent cloud
A cloud that sometimes resembles a silken scarf capping the top of a developing cumulus cloud is the ____
____ clouds form in the stratosphere and are also called mother-of-pearl clouds
The fog most likely to form on a clear, calm autumn morning above a cold lake is:
evaporation (mixing) fog
A cloud that resembles "little castles in the sky" is called
A reasonably successful method of dispersing cold fog is to:
seed the fog with dry ice
Which type of fog does not necessarily form int he air that is cooling?
evaporation (mixing) fog
If you are standing outside and notice that the sky is covered with a high, white layered cloud, and you look at the ground and observe your shadow, you may conclude that the cloud overhead is:
cirrostratus - sometimes makes a halo because it is so thin to sunlight
The highest clouds in our atmosphere are called:
upper mesosphere at 246,000 ft
The highest cirrus clouds form in the tropics at 60,000 ft
If a cloud appear s white in a visible satellite picture and gray in an infrared picture, then the cloud would most likely be a:
low cloud

low = gray
high = white
The wintertime fog that often occurs int eh central valley of CA is mainly:
radiation fog
The satellites that are positioned at the highest level above the earth's surface are"
geostationary satellites (38,500km)
RH can be 100+ without producing fog when:
there are no condensation nuclei present
Fog can be composed of ice crystals. T/F
Frost forms when water vapor changes directly into ice without first becoming a liquid. T/F
Dew most likely to form on clear, calm nights. T/F
Valleys are more susceptible to radiation fog than are hilltops. T/F
The largest concentration of condensation nuclei is usually observed at cloud level. T/F
Dry haze usually restricts visibility more than wet haze. T/F
Instruments that measure the height of a cloud's base above the ground are called
Type of uplift that occurs as air is lifted over a mountain barrier
A cloud with lightning and thunder that forms when the atmosphere is unstable
The mixing of outside air into a cloud or rising parcel of air
A vertical profile of air temperature
A measured increase in air temperature with increasing height
A low cloud that form when the atmosphere is absolutely stable
Drier region observed on the downwind (leeward) side of a mountain range
rain shadow
This term is added to altocumulus or cirrocumulus when they have towerlike extensions
A cloud associated with turbulent eddies, downwind of a mountain
Wave clouds that may form over or downwind of a mountain
The process by which a parcel expands and cools or compresses and warms with no interchange of heat with its surroundings.
This marks the base of a cloud that has formed by lifting.
LCL - lifting condensation level
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 ____
A ____ inversion forms when air slowly sinks over a wide area
The rate at which the air temperature changes inside a rising or descending parcel of unsaturated air is called the ____ ____ ____
dry adiabatic 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 ____
The rate at which the temperature changes inside a rising or descending parcel of saturated air is called the ____ ____ ____
moist adiabatic rate
If unsaturated stable air is lifted to a level where it becomes saturates and unstable, this type of instability is called ____ _____
conditional instability
Rising saturated air cools at a lesser rate than rising unsaturated air primarily because
latent heat of condensation is released in a rising parcel of saturated air
When air temperature decreases very slowly with height, and the environmental lapse rate is less than the moist adiabatic rate, the atmosphere is:
absolutely stable
When the atmosphere is absolutely unstable, the environmental lapse rate is ____ the dry adiabatic rate.
greater than
A moist layer of stable surface air can change into a deck of low stratocumulus clouds by the process of:
Clouds that appear as waves breaking along the shore are called:
For least polluted surface air, the best time of the day for a farmer to burn agricultural debris would be:
around the time of maximum surface air temperature
These two conditions, working together, will make the atmosphere the most unstable.
warm the surface and cool the air aloft
These two condition, working together, will make the atmosphere the most stable:
cool the surface and warm the air aloft
Which is not a way of producing clouds?
____ is the slow sinking of air, usually associated with high pressure areas.
An inversion represents an extremely stable atmosphere because a parcel of air that rises into an inversion will eventually become ____and ____ dense than the air surrounding it.
colder, more
Subsidence inversion are best developed with ____ pressure areas because of the ____ air associated with them.
high, sinking
The moist adiabatic rate is different from the dry adiabatic rate because:
latent heat is released inside a parcel of rising saturated air
Convection takes place over water. T/F
Most thunderstorms do not penetrate very far into the stratosphere because the stratosphere is a layer of unstable air. T/F
the stratosphere is a layer of stable air
Air motions tend to be downward around the outside of a cumulus cloud. T/F
A conditionally unstable atmosphere is stable with respect to unsaturated air and unstable with respect to saturated air. T/F
Radiational cooling of the surface at night tends to make the lower atmosphere unstable. T/F
When cloud elements become arranged in rows they are called cloud streets. T/F
In a conditionally unstable atmosphere, the environmental lapse rate will be greater than the moist adiabatic rate and less than the dry adiabatic rate. T/F
Lowering an entire layer of air will generally make it more unstable. T/F
If you were to take a trip this summer from Ohio to Nevada, you would probably observe the bases of afternoon cumulus clouds increasing in height above the ground as you travel westward. T/F
Normally, during the course of a day, the atmosphere near the surface is the most unstable during the afternoon, and the most stable in the early morning. T/F