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CDC 5 level
General Meteorology and Surface Weather Observations
124
Meteorology
Undergraduate 1
12/28/2011
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Term
How many degrees centigrade does the temperature decrease per 1,000 meters of altitude in the troposphere?
 Definition
6.5
Term
The stratosphere is characterized by
 Definition
a temperature that remains isothermal to about 100,000 feet, the strongest concentration of ozone, and excellent flying conditions.
Term
Above 13 miles, the radiation from the sun breaks down the oxygen in the atmosphere into
 Definition
ozone gas
Term
Which is true of water vapor in the atmosphere?
 Definition
The more water capor, the lighter the air will be.
Term
The earth's atmosphere receives the most heating through what process?
 Definition
Reradiated energy from the earth's surface.
Term
The two atmospheric gases most responsible for the absorption of incoming solar radiation are:
 Definition
Oxygen and ozone
Term
Explain why the sky is blue.
 Definition
Short-wave radiation is reflected by the atmospheric particles smaller than .5 microns.
Term
The driving mechanism that is mainly responsible for the earth's large-scale atmostpheric circulations is the:
 Definition
Unequal heating of the earth
Term
The three circulation cells in the three-cell theory are:
 Definition
Polar, Hadley and Ferrel
Term
Which force is the "equal and opposite reaction" to the center seeking force?
 Definition
Centrifugal
Term
Centrifugal force will increase when there is a decrease in:
 Definition
the radius of rotation.
Term
Coriolis force is created by:
 Definition
the cyclonic rotation of the earth.
Term
If you throw a ball toward a stationary target from the window of a speeding vehicle, coriolis force will cause the ball to miss the target:
 Definition
to the right.
Term
The force that is responsible for starting the horizontal movement of air over earth's surface is:
 Definition
Pressure Gradient
Term
To achieve geostrophic windflow, there must be a balance between:
 Definition
pressure gradient force and coriolis force
Term
The balance of forces needed for gradient anticyclonic circulation are pressure gradient:
 Definition
and centrifugal balances against coriolis force.
Term
The balance of forces needed to gradient cyclonic circulation is pressure gradient:
 Definition
balanced against coriolis and centrifugal forces.
Term
The areas of low pressure that correspond to the belt of low pressure at 60 N created by the 3-cell circulation are the:
 Definition
Icelandic and Aleutian lows
Term
In relation to the jet core, the greatest vertical wind shear is usually located:
 Definition
above the jet core.
Term
In relation to the jet core, the greatest horizontal wind shear is usually located:
 Definition
north of the jet core.
Term
The simplest method for locating the 500 millibar frontal zone is to:
 Definition
locate the position of the -17 Centigrade isotherm.
Term
The width of the jet stream core is approximately equal to the:
 Definition
width of the 500 millibar isotherm ribbon.
Term
What causes the subtropical jet to recurve?
 Definition
Coriolis Force
Term
The jet core that is located between the midlatitude and the tropical tropopause's is called the:
 Definition
Subtropical Jet
Term
These suggest that the jet stream is beginning to dissipate.
 Definition
"Jet fingers"
Term
Converging contours downstream of the jet stream will cause the jet to:
 Definition
Deflect toward lower heights
Term
Using average surface frontal slopes, how far behind the surface cold front is the jet stream located?
 Definition
300 miles
Term
Using average surface frontal slopes, how far ahead the surface warm front is the jet stream located?
 Definition
600 miles
Term
What will the jet stream usually do when a cold, moving, polar high stagnates and begins to warm?
 Definition
Dissipate and a new jet forms to the north.
Term
This law states that the wavelength at which maximum energy is emitted is inversly proportional to the object's temperature.
 Definition
Wein's Law
Term
Which heat transfer process involves the transfer of energy by molecular motion from hot to cold objects.
 Definition
Conduction
Term
Which heat transfer process vertically transports the atmospheric properties of heat and moisture and is more efficient method of heat transfer than by molecular motion?
 Definition
Convection
Term
Advection transfers temperature:
 Definition
horizontally by the wind.
Term
What factors must a region possess in order to facilitate air mass formation?
 Definition
Uniform surface, stagnant air, and large scale difluent flow.
Term
Which process is most responsible for the slow formation of air masses in the polar region?
 Definition
Loss of heat by radiation.
Term
Air mass stability characteristics often depend on the temperature differences between the:
 Definition
air mass and the surface over which it is traveling.
Term
A stable air mass that formed over land in the Arctic has now moved over the ocean's warmer surface. You would classify this air mass as:
 Definition
cAks
Term
What air mass classification signifies an unstable, maritime tropical air mass that is colder than the surface it is moving over?
 Definition
mTku
Term
What air mass classification signifies a stable, continental polar air mass that is warmer than the surface it is moving over.
 Definition
cPws
Term
What air mass forms over land only during the summer?
 Definition
cT
Term
What factors act as air mass modifiers?
 Definition
Radiation loss, thermodynamics, advection, and mechanical mixing.
Term
It is winter. A cPk air mass is moving over the Great Lakes. In this situation, the southern shores of the Great Lakes will experience:
 Definition
heavy snow.
Term
Which air mass involves most of the windertime storms for the North American Pacific coast?
 Definition
mT
Term
In the summer, the continental highs:
 Definition
Dissipate over the heated land and the cP source regions move farther north.
Term
Continental tropical air masses are usually assocaited with:
 Definition
thermal lows
Term
The rate that an air mass modifies depends on the:
 Definition
temperature differences between the new surface and the air mass, the nature of the surface over which it moves, and the speed with which the air mass travels.
Term
The weather characteristics of a particular month in a given locality are governed by:
 Definition
effects of local topography and proximity to a zone of convergence.
Term
Surface pressure changes largely controlled by:
 Definition
mass changes in the upper troposphere
Term
Horizontal divergence within an air mass will:
 Definition
vertically contract the original column of air and then expand it horizontally.
Term
As air converges at the surface and toward the center of a layer, there will be horizontal:
 Definition
contraction and vertical expansion.
Term
An increase of mass in a column of air will cause the surface pressure to:
 Definition
increase
Term
A decrease of mass in a column of air will cause the surface pressure to:
 Definition
decrease
Term
The primary cause of surface pressure changes for a dynamic low is net:
 Definition
divergence aloft.
Term
The damper effect is comprised of upper-level:
 Definition
convergence and surface high pressure
Term
You are evaluating a jet maximum in straight line flow. To do this properly, you would locate the maximum area of convergence at the:
 Definition
left rear quadrant.
Term
A low-pressure system undergoing cyclogenesis is said to be:
 Definition
forming or deepening.
Term
When the central pressure of an anticyclone is rising, you can infer the anticyclone is:
 Definition
building.
Term
A high-pressure system undergoes anticyclolysis when the clockwise circulation area:
 Definition
decreases or disappears.
Term
A cyclone that develops on a polar front, does not intensify significantly, and never occludes is called:
 Definition
stable
Term
After warm air with an unstable wave is pushed aloft and cuts off from a cyclone the cyclone will become:
 Definition
barotropic and begin to fill.
Term
Unstable waves are classified as:
 Definition
baroclinic
Term
In the barolcinic instability process:
 Definition
potential energy is transferred to the major short wave by thermal advection
Term
Aloft, during the baroclinic instability process, the thermal wave and contour wave are:
 Definition
out of phase and cold air advection occurs into the contour trough.
Term
An intense cyclogenesis normally occurs in troughs with a:
 Definition
negative tilt that is oriented northwest/southeast
Term
When using Pettersen's rule, the factors needed for cyclogenesis are upper-level:
 Definition
divergence and a frontal zone where thermal advection is weak.
Term
What causes the surface low to deepen during the self-development process?
 Definition
Divergence
Term
A low dissipates after proceeding through its entire life cycle which ranges from the:
 Definition
bottom up as boundary layer convergence adds mass to the column of air.
Term
How many stages are there in the life cycle of a low
 Definition
Five
Term
In the life cycle of a low, the wave will reach its maximum intensity in the:
 Definition
mature stage
Term
Anticyclongenesis typically occurs at, and just downstream from, long-wave
 Definition
ridges under confluent flow aloft
Term
What causes a surface high to build during the self-development process?
 Definition
Convergence aloft
Term
Which is primarly responsible for low-level divergence acting as a braking mechanism for a high?
 Definition
Friction
Term
A warm barotropic high:
 Definition
has great vertical extent and its axis tilts with height.
Term
The best sources for identifying a frontal inversion are the:
 Definition
temperature and dew point curves and the vertical wind distribution
Term
With the passage of a cold front in the Northern Hemisphere, the horizontal wind direction will:
 Definition
shift in a clockwise direction
Term
The cold conveyor belt originates in the low levels that are located:
 Definition
east of a low center and flow westward.
Term
The average slope of a cold front is:
 Definition
1/30 to 1/100
Term
A warm frontal occlusion occurs when the cool air
 Definition
behind the cold front overrides the colder air ahead of the warm front.
Term
With an active cold front, the net flow is:
 Definition
upward
Term
An inactive cold front is characterized by a relatively:
 Definition
steeper slope, a narrow weather pattern, and is called katafront.
Term
When an inactive front passes your station, the dew points will
 Definition
decreases sharply with the passage.
Term
When only high and middle clouds are associated with a warm front, the:
 Definition
overrunning warm air is dry
Term
Which region of the United States facors the development of frontal occlusions?
 Definition
North
Term
In a cold occlusion, the coldest air is found:
 Definition
behind the cold front
Term
In a warm frontal occlusion, the coldest air is found:
 Definition
ahead of the warm front
Term
The frontolytic processess are most effective:
 Definition
in the lower layers of the atmosphere
Term
Frontogenesis requires two adjacent air masses with:
 Definition
different densities and a wind flow to bring the air masses together.
Term
The atmospheric properties that can be a measure of the strength of a frontal system are thickness gradient,
 Definition
temperature gradient, lapse rate, turbulence and wind shear.
Term
Low cloud bases range from:
 Definition
near the surface to 6,500 feet above ground level.
Term
Which low cloud type and classifiction is identified by the presence of a cirriform anvil?
 Definition
Cumulonimbus-L9
Term
The best way to distinguish stratocumulus from altocumulus clouds is to use:
 Definition
the size of the elements.
Term
The primary difference between stratus and altostratus clouds is:
 Definition
the composition of the clouds.
Term
How would you classify middle clouds that can lower to within several hundred feet of the surface?
 Definition
M2
Term
A corona is often present at night with:
 Definition
altocumulus clouds
Term
Cirrus clouds in the form of an anvil are classified as:
 Definition
H3
Term
Which high cloud can occasionally be so transparent that the only indication of its presence is a halo phenomenon?
 Definition
H7
Term
Which high cloud classifiction is also referred to as a mackerel sky?
 Definition
Cirrocumulus-H9
Term
Which orographic cloud resembles an almond or a fish?
 Definition
Lenticular
Term
"Clouds or obscuring phenomena that have bases at the same approximate level" is the definition of:
 Definition
a layer
Term
Pilot reported ceiling heights must be converted from height above:
 Definition
mean sea level to height above ground level.
Term
What color balloon would you use to determine the ceiling heights of thin cloud?
 Definition
Red
Term
You are preparing to use a convective cloud height table to determine the heights of clouds. To do this properly, you must first determine the:
 Definition
dew point temperature and free air temperature.
Term
The most desirable night-visibility markers are:
 Definition
unfocused lights
Term
How do you report prevailing visibility at CONUS stations and overseas stations?
 Definition
Statute miles for CONUS and meters for overseas stations.
Term
You are reporting the visibility for more than one sector. To do this properly, you would list the sectors in a:
 Definition
Clockwise direction starting from the northernmost sector.
Term
The designated runway visual range (RVR) runway is:
 Definition
any runway that has been instrumented with a transmissometer.
Term
For a runway visual range (RVR) report of R15/1600, what is the visual range that a pilot can expect to see down the runway?
 Definition
1,600 meters
Term
The three main forms of precipitation are liquid,
 Definition
freezing, and frozen.
Term
What type of precipitation might you observe with clear skies?
 Definition
ice crystals
Term
You would classify precipitation as intermittent if it:
 Definition
stopped and started at least once within the preceding hour
Term
What is the intensity of snow which restricts visibility to less than 1/4 mile?
 Definition
Heavy
Term
Precipitation is reported to the nearest:
 Definition
.01 of an inch
Term
The distinguishing feature of any tornadic activity is:
 Definition
the funnel-shaped appendage that hangs from the base of the clouds.
Term
A thunderstorm is present and occurring at your station. In addition, the local noice level is preventing you from hearing the thunderstorm. For observation purposes you would say:
 Definition
hail is falling
Term
A thunderstorm offically ends:
 Definition
fifteen minutes after the last occurence of thunder, hail, or lightning.
Term
For observing purposes, four hydrometers are considered to be obstructions to vision. They include fog, blowing snow,:
 Definition
freezing fog and blowing spray.
Term
Blowing spray is reported only at sea stations near large bodies of water and when visibility at eye level is rescricted to:
 Definition
9,000 meters or less
Term
Which type of obstruction to vision is classified as a lithometer?
 Definition
smoke
Term
What pressure value is the basis for determinig all other pressure values?
 Definition
Station pressure
Term
What is the reference level for all pressure values?
 Definition
Sea-level pressure
Term
Which is the calculated sea-level pressure in inches of mercury?
 Definition
Altimeter setting
Term
The temperature an air parcel would have if it were cooled adiabatically to saturation at constant pressure by evaporation of water into it is called:
 Definition
wet bulb temperature
Term
Wind observing equipment is oriented to:
 Definition
magnetic north
Term
A sudden increase of wind speed of at least 16 knots and a sustained average of 22 knots (or more) that is maintained for at least 1 minute before the speed diminishes is called a:
 Definition
squall
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