exam 2 chap 6-10
In the above diagram, the environmental lapse rate (ELR) is:
Conditionally unstable The ELR here is between the MALR and DALR, meaning that the atmosphere is conditionally unstable.
Based on the above diagram, a rising air parcel given an initial push will:
Continue to rise freely if saturated, but return to its initial position if unsaturated
Based on the above diagram, a rising air parcel given an initial push will:
Continue to rise freely if saturated, but return to its initial position if unsaturated In conditional instability, the "condition" is saturated. Saturated air parcels will be warmer than the environment and continue to rise, while unsaturated parcels will be colder than the environment and return to their initial position.
The ____ force is an apparent force created by Earth's rotation.
Coriolis
The growth of a precipitation particle by the collision of an ice crystal (or snowflake) with a supercooled liquid droplet is called
accretion
To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for
altitude
The dry adiabatic rate is ____ greater than the moist adiabatic rate.
always
Conditional instability occurs whenever the environmental lapse rate is ____ the moist adiabatic rate and the dry adiabatic rate.
between
The elevation where clouds form is called ____ level.
condensation
If rain falls on one side of a street and not on the other side, the rain most likely fell from a ____ cloud.
cumulonimbus
The most common ice crystal shape is
dendrite
The lightest form of rain is
drizzle
An afternoon sky full of cumulus humilis clouds with little vertical growth indicates ____ weather.
fair
Surface winds blow across isobars at an angle and the pressure gradient force is balanced by the ____ force and the Coriolis force.
frictional
The region of a cloud where only ice particles exist is called
glaciated
Which of the following might be mistaken for hail?
graupel
The contour lines drawn on a 500 mb chart are lines of constant
height
A typical raindrop is about ____ than a typical cloud droplet.
one hundred times larger
Eddies that form both close to the mountain and beneath each wave crest are called
rotors
Air which resists vertical displacements is considered to be
stable
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
Most thunderstorms do not extend very far into the stratosphere because the air in the stratosphere is
stable
Which cloud would most likely produce drizzle?
stratus
When cloud elements become arranged in rows they are called cloud
streets
Fallstreaks usually ____ before reaching the ground.
sublimate
Inversions that form as air slowly sinks over a large area are called ____ inversions.
subsidence
What transfers heat upward into the atmosphere?
thermals
In the tropics, pressure rises and falls in a regular pattern ____ a day.
twice
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
There is always a strong pressure gradient force directed _________.
upward
The majority of the United States lies within this wind belt
westerlies
A station at an altitude of 900 m (about 3,000 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?
1,020 mb
Dry adiabatic cooling and warming rates are approximately ____ of change in elevation.
10 degrees Celsius for every 1000 m
If rising air cools to its dew-point temperature, the relative humidity becomes ____.
100%
Which environmental lapse rate represents the most unstable atmosphere in a layer of unsaturated air?
11°C per 1,000 m
The subtropical jet stream is usually found between
20° to 30° latitude, 200-mb level.
In terms of the three-cell general circulation model, the driest regions of Earth should be near
30° latitude and the polar regions.
Raindrops that reach Earth's surface are seldom larger than
5 mm
A geostrophic wind is a wind that results from a balance between the ____ force and the ____ force.
Coriolis; pressure gradient
The two ocean currents, warm and cold, that produce fog off the coast of Newfoundland are the
Gulf Stream and LabradorCurrent.
The large thermally driven convection cell that is driven by convective "hot" towers along the equator is the
Hadley cell.
Which statement describes the polar front jet stream?
It forms near the boundary called the polar front.
Which statement describes the subtropical jet stream?
It generally blows from west to east.
A condition where the central and eastern tropical Pacific Ocean turns cooler than normal is called
La Niña
A condition where the central and eastern tropical Pacific Ocean turns cooler than normal is called
La Niña.
A wind reported as 45°would be a wind blowing from the:
NE.
Which condition below is necessary for a layer of altostratus clouds to change into altocumulus?
The top part of the cloud deck cools while the bottom part warms.
Precipitation with the greatest size (diameter) is
a hailstone.
A supercooled cloud droplet is
a liquid droplets observed at temperatures below 0°C (32°F).
Which cloud type below will only produce precipitation by the collision-coalescence process?
a thick, warm cumulus cloud
A surface low pressure center is generally associated with ____ on an upper level isobaric chart.
a trough
If the environmental lapse rate is less than the moist adiabatic rate, the atmosphere is
absolutely stable.
In the Northern Hemisphere, the polar jet stream is strongest when
air north of the polar front is much colder than air south of the polar front.
Which of the following sets of conditions would produce a cumulus cloud with the lowest base?
air temperature 90°F, dew point temperature 60°F
To correctly monitor horizontal changes in air pressure, the most important correction for a mercury barometer is the correction for
altitude.
Which condition would be described as the most stable?
an inversion
The pressure gradient force is directed from higher pressure toward lower pressure
at all places on Earth.
Fallstreaks most often form with
cirrus clouds.
What is a serious hazard to aircraft?
clear-air turbulence
The wind around a surface high pressure center in the Northern Hemisphere blows
clockwise and outward from the center.
On the eastern side of the Rocky Mountains, chinook winds are driest when
clouds form and precipitation falls on the upwind side of the mountains.
An inversion represents an extremely stable atmosphere because air that rises into the inversion will eventually become ____ and ____ dense than the surrounding air.
colder; more
The heat from a chinook wind is generated mainly by
compressional heating.
On a 500 millibar chart, ____ are drawn to represent horizontal changes in altitude which correspond to horizontal changes in pressure.
contour lines
Clouds and precipitation are frequently found on the downwind side of a large lake. This would indicate that the air on the downwind side is
converging and rising.
If rain falls on one side of a street and not on the other side, the rain most likely fell from a ____ cloud.
cumulonimbus
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 ____ in the cold column.
decrease; more slowly than
In a rising unsaturated thermal, the dew-point temperature
decreases at a slower rate than the parcel temperature.
Thermal turbulence above the surface is usually most severe
during maximum surface heating.
The speed of falling cloud droplet increases until the air resistance
equals the pull of gravity.
An example of orographic clouds would be clouds
forming on the windward slope of a mountain.
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?
freezing rain
Meridional wind-flow patterns go
from either north-to-south or south-to-north.
An offshore wind blows
from land to water.
For sub-freezing temperatures, the saturation vapor pressure just above a liquid water surface is ____ the saturation vapor pressure above an ice surface.
greater than
In a conditionally unstable atmosphere, the environmental lapse rate will be ____ the moist adiabatic rate and ____ the dry adiabatic rate.
greater than; less than
Isobaric surfaces are ____ in warm, less-dense air and ____in cold, more-dense air.
higher; lower
During the ice crystal process of rain formation,
ice crystals grow larger at the expense of the surrounding liquid cloud droplets.
The jet stream flows
in a wavy pattern from west to east.
During the summer along the coast, a sea breeze is usually strongest and best developed
in the afternoon.
Which pressure unit is most commonly used in aviation?
inches of mercury
As an air parcel aloft moves northward from the equator, it moves closer to Earth's axis of rotation. Because of the conservation of angular momentum, the air parcel's motion should
increase in speed.
A thermally direct cell is one that
is driven by energy from the Sun.
Wind blowing with sufficient force to rip the roof off buildings
is uncommon.
The nighttime counterpart of the sea breeze circulation is called
land breeze.
The difference between "moist" and "dry" adiabatic rates is due to the fact that
latent heat is released by a rising parcel of saturated air.
Which of the below determines how high a wind wave will grow over the open ocean?
length of time the wind blows over the water
The unit of pressure most commonly found on a surface weather map is
millibars or hectopascals.
The rate at which the temperature changes inside a rising (or descending) parcel of saturated air is called the ____ rate.
moist adiabatic lapse
At Earth's surface, a rising saturated air parcel cools at the
moist adiabatic rate.
The slowing of the wind due to the random motion of air molecules is called
molecular viscosity.
Pressure changes
more rapidly in the vertical direction than in the horizontal.
Because of friction, surface winds move ____ winds aloft with the same pressure gradient.
more slowly than
The low-level jet that forms over the Central Plains of the United States in the summer appears to be responsible for
nighttime thunderstorms.
The intertropical convergence zone (ITCZ) is a region where
northeast trades converge with the southeast trades.
The world's deserts are found at 30° latitude because
of the sinking air of the subtropical highs.
The force that would cause a stationary parcel of air to begin to move horizontally is called the
pressure gradient force.
The amount of pressure change that occurs over a given horizontal distance is called the
pressure gradient.
On an isobaric surface,
pressure is constant.
In middle latitudes, when an area of high pressure approaches a city, surface pressure usually ____. When it moves away, pressure usually ____.
rises; falls
The largest amount of latent heat gets released in a ____ parcel of ____ saturated air.
rising; warm
When a sea breeze moving east meets a sea breeze moving west, they form a
sea breeze convergence zone.
Convective instability is associated with the development of
severe storms, such as thunderstorms and tornadoes.
The primary method used in preventing the growth of large, destructive hailstones is to inject a thunderstorm with large quantities of
silver iodide.
Which statement below best describes the curvature effect?
small droplets evaporate more quickly than large droplets.
Condensation onto hygroscopic nuclei is possible at relative humidities less than 100 percent due to the
solute effect.
On a weather map of the Northern Hemisphere, the trade winds would be observed
south of the subtropical highs.
Generally, in the Northern Hemisphere during July, we would expect to find the tropical easterly jet stream
south of the upper-level subtropical high.
On a clear, windy day, the depth to which mixing occurs above the surface depends upon
surface heating.
The dry adiabatic lapse rate is the rate at which
temperature changes in a rising or descending parcel of unsaturated air.
In the three-cell model of the atmosphere, upper level winds are incorrectly predicted to flow from ____.
the east
The ultimate cause of jet streams is
the energy imbalance between high and low latitudes.
In terms of the three-cell model of the general circulation, areas of surface low pressure should be found at
the equator and 60° latitude.
Contact freezing is
the freezing of supercooled droplets by contact with a nucleus.
A wind rose indicates
the percentage of time that the wind blows from different directions.
Upwelling is
the rising of cold water from below.
The size and shape of a turbulent eddy depends upon
the size and shape of the obstacle.
The Ekman Spiral describes
the turning of water with depth.
A knowledge of air stability is important because it determines
the vertical motion of air.
Upper-level winds in the middle latitudes of both hemispheres generally blow from ____.
the west
If huge waves pound against the beach communities of Southern California for several days during clear, calm weather, it is a good bet that
the winds are strong somewhere out over the Pacific Ocean.
The land/sea breeze, lake breeze, and mountain/valley breeze are examples of
thermal circulations.
On a surface weather map during the month of July, one would expect to find what type of pressure system over the desert southwest of the United States?
thermal low
If you observe large raindrops hitting the ground, you could probably say that the cloud overhead was ____ and had ____ updrafts.
thick; strong
Wind gusts are caused by
turbulent eddies.
In a sky filled with scattered cumulus humilis clouds, rising motions are found ____ the clouds and sinking motions are found ____ the clouds.
under; between
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 cold water observed along the northern California coast in summer is due mainly to
upwelling.
Chinook winds are
warm, dry downslope winds.
Which below best describes the solute effect?
water droplets dissolve hygroscopic nuclei and condensation can occur at relative humidities less than 100 percent
The synoptic scale describes circulations on the ____ scale.
weather-map
Zonal flow wind-flow patterns are associated with
west-to-east flows.
Due to Hadley cell formation and the Coriolis force in both hemispheres, winds aloft flow
westerly.
Upwelling occurs along the northern California coast because
winds cause surface waters to move away from the coast.
The north-south temperature contrast along the polar front is strongest in ____ and weakest in ____.
winter; summer
What is considered standard sea-level atmospheric pressure in millibars?
1013.25 mb
Suppose the wind speed increased from 5 mph to 10 mph. We can conclude that the force exerted by the wind increased by a factor of
4
The Coriolis force acts at a ____ degree angle to the wind.
90
