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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 |
Temperature that remains isothermal to about 100,000 feet, the strongest concentration of ozone and excellent flying conditions. |
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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 are |
Oxygen and ozone. |
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The driving mechanism that is mainly responsible for the earth's large-scale atmospheric circulations is the |
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, coriolis force (CoF) will cause the ball to miss the target |
To the right. |
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The force that is responsible for starting the horizontal movement of air over earth's surface is |
Pressure Gradient force. |
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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 60N created by the 3-cell circulation are the |
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 500 millibar 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. |
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"Jet Fingers" |
Suggest that the jet stream is beginning to dissipate. |
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Converging contours downstream of the jet stream will cause the jet to |
Deflect toward lower heights. |
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Using average surface frontal slopes, how far ahead of the surface warm front is the jet stream located? |
600 miles. |
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Which heat transfer process involves the transfer of energy by molecular motion from hot to cold objects? |
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 than the surface it is moving over? |
mTku |
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What air mass classification signifies a stable, continental polar air mass that is warmer than the surface it is moving over? |
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 shores of the Great Lakes will experience |
Heavy snow. |
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Which air mass involves most of the wintertime storms for the North American Pacific coast? |
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 of 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 the 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 fromt a cyclone, the cyclone will become |
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 Petterson's rule, the factors needed for cyclogenesis are upper-level |
Divergence and a frontal zone where the 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? |
5. |
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In the life cycle of a low, the system will evolve into a cold barotrpic low in the |
Dissipation stage. |
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Anticyclogeneis typically occurs at, and just downstream from, long-wave |
Ridges and 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 a high? |
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 will |
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. |
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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 the katafront. |
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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 warm front. |
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Frontogenesis requires two adjacent air masses with |
Different densities and a wind flow to bring the air masses together. |
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The frontolytic processes are most effective |
In the lower layers of the atmosphere. |
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The difference in cloud classification betweel 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 presence is a halo phenomenon? |
H7. |
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Which high cloud classification is also referred to as mackerel sky? |
Cirrocumulus-H9 |
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Which orographic cloud resembles an almond or a fish? |
Lenticular. |
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"Clouds or obscuring phenomena that have bases at the same approximate level" is the definition of |
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 prearing to use a convective cloud height table to determine the heights of clouds. To do this properly, you must first determine the |
Dew-point temperature and free-air temperature. |
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How do you report prevailing visibility at US stations and overseas stations? |
Statute miles for US stations and meters ofr overseas stations. |
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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 a pilot can expect to see down the runway? |
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 overflow unit of the rain gauge. |
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The distinguishing feature of any tornadic activity is |
The funnel-shaped appendage that hands 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 preventing you from hearing the thunderstorm. For observation purposes you would say |
Hail is falling. |
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A thunderstorm officially ends |
15 minutes after the last occurrence of thunder, hail or lightning. |
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For observing purposes, 5 hydrometers are considered to be obstructions to vision. They include mist, fog, blowing snow, |
Freezing fog and blowing spray. |
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Blowing spray is reportedly only at sea stations near large bodies of water and when visibility at eye level is restricted to |
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 content and pressure to reach saturation is called |
Dew point. |
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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 |
Wet bulb temperature. |
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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 called a |
Wind shift. |