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100 Cards in this Set
- Front
- Back
How many degrees centigrade does the temperature decrease per 1,000 meters of altitude in the troposphere? |
6.5 |
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The stratosphere is characterized by |
a temperature that remains isothermal to about 100,000 feet, the strongest concentration of |
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Above 13 miles, the radiation from the sun breaks down the oxygen in the atmosphere into |
ozone gas. |
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Which statement best describes water vapor in the atmosphere? |
The more water vapor, the lighter the air will be. |
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The two atmospheric gases most responsible for the absorption of incoming solar radiation |
oxygen and ozone. |
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The driving mechanism that is mainly responsible for the earth’s large-scale atmospheric |
unequal heating of the earth. |
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Which force is described as any center-seeking force? |
Centripetal. |
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Which force is the “equal and opposite reaction” to the center-seeking force? |
Centrifugal. |
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Centrifugal force (CeF) will increase when there is a decrease in |
the radius of rotation. |
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Coriolis force (CoF) is created by |
the cyclonic rotation of the earth. |
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If you throw a ball towards a stationary target from the window of a speeding vehicle, |
to the right. |
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The force that is responsible for starting the horizontal movement of air over earth’s surface |
pressure gradient. |
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The balance of forces needed for gradient cyclonic circulation is pressure gradient |
balanced against coriolis and centrifugal forces |
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The areas of low pressure that correspond to the belt of low pressure at 60°N created |
Icelandic and Aleutian lows. |
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In relation to the jet core, the greatest vertical wind shear is usually located |
above the jet core |
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In relation to the jet core, the greatest horizontal wind shear is usually located |
north of the jet core |
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The simplest method for locating the 500 millibar frontal zone is to |
locate the position of the -17 centigrade isotherm |
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The width of the jet stream core is approximately equal to the |
width of the 500mb isotherm ribbon |
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Where are the greatest velocities located in relation to the subtropical jet (SJT)? |
in the region of confluence of the STJ and PFJ |
|
“Jet fingers” |
suggest that the stream is becoming discontinuous. |
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Converging contours downstream of the jet stream will cause the jet to |
deflects toward lower heights |
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Using average surface frontal slopes, how far ahead of the surface warm front is the jet |
600 miles |
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Which heat transfer process involves the transfer of energy by molecular motion from hot to |
conduction |
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Advection transfers temperature |
horizontally by the wind |
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What factors must a region possess in order to facilitate air mass formation? |
uniform surface, stagnant air and large-scale difluent flow. |
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Which process is most responsible for the slow formation of air masses in the polar region? |
Loss of heat by radiation. |
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Air mass stability characteristics often depend on the temperature difference between the |
air mass and the surface over which it is traveling |
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How would you classify a stable air mass that formed over land in the Arctic has now moved over the ocean's warmer surface? |
cAks |
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What air mass classification signifies an unstable, maritime tropical air mass that is colder |
mTku |
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What air mass classification signifies a stable, continental polar air mass that is warmer than |
cPws |
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What air mass forms over land only during the summer? |
cT |
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As an air mass is heated from below, there will be increased |
instability and an increased lapse rate. |
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It is winter. A cPk air mass is moving over the Great Lakes. In this situation, the southern |
heavy snow |
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Which air mass involves most of the wintertime storms for the North American Pacific |
mT |
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Continental tropical air masses are usually associated with |
thermal lows |
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The rate that an air mass modifies depends on the |
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. |
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The weather characteristics of a particular month in a given locality are governed by |
effects the local topography and proximity to a zone of convergence |
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Surface pressure changes are largely controlled by |
mass changes in the upper troposphere. |
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Horizontal divergence within an air mass will |
vertically contract the original column of air and then expand it horizontally. |
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As air converges at the surface and toward the center of a layer, there will be horizontal |
contraction and vertical expansion. |
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An increase of mass in a column of air will cause the surface pressure to |
increase. |
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In the chimney effect, the maximum upward vertical wind motion will be located |
at the level of nondivergence (LND). |
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The primary cause of surface pressure changes for a dynamic low is net |
divergence aloft. |
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The damper effect is comprised of upper-level |
convergence and surface high pressure. |
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A low-pressure system undergoing cyclogenesis is said to be |
forming or deepening. |
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When the central pressure of an anticyclone is rising, you can infer the anticyclone is |
building. |
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A high-pressure system undergoes anticyclolysis when the clockwise circulation area |
decreases or disappears. |
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An unstable wave cyclone is one where the amplitude |
increases with time and the wave deepens. |
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After warm air with an unstable wave is pushed aloft and cuts off from a cyclone, the |
barotropic and begin to fill. |
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Unstable waves are classified as |
baroclinic lows. |
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In the baroclinic instability process, |
potential energy is transferred to the major short wave by thermal advection. |
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When using Petterssen’s rule, the factors needed for cyclogenesis are upper-level |
divergence and a frontal zone where thermal advection is weak. |
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What causes the surface low to deepen during the self-development process? |
Divergence aloft. |
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A low dissipates after proceeding through its entire life cycle which ranges from the |
bottom up as boundary layer convergence adds mass to the column of air. |
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How many stages are there in the life cycle of a low? |
Five. |
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In the life cycle of a low, the system will evolve into a cold barotropic low in the |
dissipation stage. |
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Anticyclogenesis typically occurs at, and just downstream from, long-wave |
ridges under confluent flow aloft. |
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What causes a surface high to build during the self-development process? |
Convergence aloft. |
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Which is primarily responsible for low-level divergence acting as a braking mechanism for |
Friction. |
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A warm barotropic high is a type of pressure system that |
has great vertical extent and is usually found over water areas. |
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In regards to types of pressure systems, a heat low is a |
warm barotropic low that forms during the summer |
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With the passage of a cold front in the Northern Hemisphere, the horizontal wind direction |
shift in a clockwise direction. |
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The cold conveyor belt originates in the low levels that are located |
east of a low center and flow westward. |
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The average slope of a cold front is |
1/30 to 1/100. |
|
A warm frontal occlusion occurs when the cool air |
behind the cold front overrides the colder air ahead of the warm front. |
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In comparison to an active cold front, an inactive cold front is characterized by a relatively |
steeper slope, a narrow weather pattern, and is called katafront. |
|
When an inactive front passes your station, the dew points will |
decrease sharply with the passage. |
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When only high and middle clouds are associated with a warm front, the |
overrunning warm air is dry. |
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In a cold occlusion, the coldest air is found |
behind the cold front. |
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In a cold occlusion, which type of front, if any, is found aloft? |
The occlusion. |
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Frontogenesis requires two adjacent air masses with |
different densities and a wind flow to bring the air masses together. |
|
The frontolytic processes are most effective |
in the lower layers of the atmosphere. |
|
The difference in cloud classification between L1 and L7 is |
precipitation. |
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Which low cloud type and classification is identified by the presence of a cirriform anvil? |
Cumulonimbus-L9. |
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The best way to distinguish stratocumulus from altocumulus clouds is to use |
the size of the elements. |
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A corona is often present at night with |
altocumulus clouds. |
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Cirrus clouds in the form of an anvil are classified as |
H3. |
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Which high cloud can occasionally be so transparent that the only indication of its |
H7. |
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Which high cloud classification is also referred to as a mackerel sky? |
Cirrocumulus-H9. |
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Which orographic cloud resembles an almond or a fish? |
Lenticular. |
|
“Clouds or obscuring phenomena that have bases at the same approximate level” is the |
a layer. |
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What color balloon would you use to determine the ceiling heights of thin clouds? |
Red. |
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You are preparing to use a convective cloud height table to determine the heights of clouds. |
dew-point temperature and free-air temperature. |
|
How do you report prevailing visibility at US stations and overseas stations? |
Statute miles for US stations and meters for overseas stations. |
|
To properly report the visibility for more than one sector, you would list the sectors in a |
clockwise direction starting with the northernmost sector. |
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For a runway visual range (RVR) report of R22/1000V1600FT, what is the visual range that |
1,000 to 1,600 feet varying. |
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What type of precipitation might you observe with clear skies? |
Ice crystals. |
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You would classify precipitation as intermittent if it |
stopped and started at least once within the preceding hour. |
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When frozen precipitation is expected, you would |
collect it in the in the overflow unit of the rain gauge. |
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The distinguishing feature of any tornadic activity is |
the funnel-shaped appendage that hangs from the base of the cloud. |
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A thunderstorm is present and occurring at your station. In addition, the local noise level is |
hail is falling. |
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A thunderstorm officially ends |
fifteen minutes after the last occurrence of thunder, hail, or lightning. |
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For observing purposes, five hydrometers are considered to be obstructions to vision. They |
freezing fog, and blowing spray. |
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Blowing spray is reported only at sea stations near large bodies of water and when visibility |
9,000 meters or less. |
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What pressure value is the basis for determining all other pressure values? |
Station pressure. |
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What is the reference level for all pressure values? |
Sea-level pressure. |
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The temperature to which a given parcel of air must be cooled, with constant water vapor |
dew point. |
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The temperature an air parcel would have if it were cooled adiabatically to saturation at |
wet bulb temperature. |
|
Wind observing equipment is oriented to |
magnetic north. |
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A change in wind direction of 45 (or more) that takes place in less than 15 minutes is |
wind shift. |