Met Gen 7 Flashcards
Localized meteorological conditions that produce intense wind shears at arctic airports as well as at airports situated along the coasts of Canada’s mountainous regions could be due to the presence of:
A) Nocturnal jet streams.
B) High level temperature inversions.
C) Eroding anticyclonic ridges.
D) Valley, katabatic, or funnel winds.
D) Valley, katabatic, or funnel winds.
One of the signposts for the existence of a mountain wave is:
A) Widespread convective cloud development downwind of the mountain range.
B) The presence of very strong anabatic winds.
C) The formation of scud roll cloud downwind from the first wave crest.
D) The presence of altocumulus standing lenticular clouds.
D) The presence of altocumulus standing lenticular clouds.
The lowest group of stationary clouds associated with a mountain wave is:
A) Altocumulus standing lenticular.
B) Rotor cloud.
C) Wall cloud.
D) Altocumulus castellanus.
B) Rotor cloud.
Rotor clouds found during mountain wave activity are located:
A) Over the mountain tops several thousand feet above.
B) Located at ridge top heights with their bases often extending below.
C) Beneath the wave crest within the mountain wave.
D) Both (B) and (C) are correct.
D) Both (B) and (C) are correct.
Where are lenticular clouds located in a mountain wave?
A) Over the top of the mountain peaks.
B) At the wave crests.
C) Under the wave crest at ridge top heights downstream of a mountain range.
D) At the troughs of the mountain waves.
B) At the wave crests.
The most powerful rotor associated with the presence of a mountain wave is located:
A) In the proximity of the first wave crest.
B) Approximately 50NM downwind from the lee slopes.
C) Always well below the crest of the mountain ridge and usually topped at 2000 feet above the ground.
D) Just below the tropopause, downwind of the third wave crest.
A) In the proximity of the first wave crest.
The part of a mountain wave system that usually presents the most severe turbulence is located:
A) In that area where the cap clouds spill over the leeward slopes.
B) Near the wave that is farthest from the mountain range.
C) Within that layer that is bounded by the ground and the top of the rotor cloud.
D) Just above the downwind portion of each wave crest.
C) Within that layer that is bounded by the ground and the top of the rotor cloud.
Severe turbulence at very high altitudes is likely to be associated with a mountain wave system when:
A) A warm high pressure system at the 400hPa level lies just upwind of the mountain range and parallel to it.
B) The wavelength of the standing wave is less than 5NM.
C) The air mass is statically unstable and a very unstable layer lies above the mountain range.
D) There is a jet stream wind aloft that is orientated perpendicular to the axis of the mountain range.
D) There is a jet stream wind aloft that is orientated perpendicular to the axis of the mountain range.
Which of the following statements is correct with reference to a mountain wave system?
A) Altimeter readings are likely to over-read when flying through the crest of a mountain wave.
B) This system can be easily located because characteristic cloud types are always present.
C) The freezing level is at a uniform altitude downwind from the range.
D) The most severe wave is the one that is the greatest distance downwind from the mountain range.
A) Altimeter readings are likely to over-read when flying through the crest of a mountain wave.
The tropopause is defined as the boundary between the troposphere and the stratosphere. The tropopause can be identified during a climb in the upper troposphere by the occurrence of:
A) A sudden change in the direction of the thermal wind.
B) An abrupt change in the temperature lapse rate.
C) A marked increase in air density.
D) A dramatic increase in the static air temperature.
B) An abrupt change in the temperature lapse rate.
The tropopause:
A) Shows little change in height across upper fronts.
B) Is lower over the equator than over the pole.
C) Is located just above a region of very weak westerly flow.
D) Acts as a lid on the clouds and weather of the troposphere.
D) Acts as a lid on the clouds and weather of the troposphere.
There is an abrupt change in the height of the tropopause over each:
A) Region of surface pressure field change.
B) Major topographical feature such as a mountain range.
C) Latitude interval of 15 degrees.
D) Frontal surface.
D) Frontal surface.
Which of the following air masses would most likely have the highest tropopause height?
A) mT.
B) mA.
C) mP.
D) cA
A) mT.
The tropopause is:
A) Higher and colder over a warm air mass.
B) Lower and warmer over a warm air mass.
C) Higher and colder over a cold air mass.
D) Lower and colder over a cold air mass.
A) Higher and colder over a warm air mass.
With respect to the tropopause, which of the following is a true statement?
A) It is found at a constant altitude over North America.
B) It’s altitude is great over the polar region than over the equatorial region.
C) The international Standard Atmosphere assumes the height of the tropopause to be 39,060 feet ASL.
D) It’s altitude is lower over the polar region than over the equatorial region.
D) It’s altitude is lower over the polar region than over the equatorial region.
In the International Standard Atmosphere the height of the tropopause and its temperature are specified as:
A) 29,000 ft and -43 degrees C.
B) 36,089 ft and -56.5 degrees C.
C) 39,060 ft and -55.6 degrees C.
D) 45,000 ft and -75 degrees C
B) 36,089 ft and -56.5 degrees C.
What causes jet streams to form?
A) A strong pressure gradient force between a low and a high-pressure area.
B) A strong pressure gradient force that is derived from a strong temperature contrast on the earths surface.
C) The Hadley Cell of circulation in the subtropics undergoes a long and slow acceleration as coriolis deflects the air to the right in the northern hemisphere.
D) Both (B) and (C) and correct.
D) Both (B) and (C) and correct.
Along with the presence of steep horizontal pressure gradients, which of the following constitutes a major factor in the formation of jet streams?
A) Centripetal force.
B) Linear momentum.
C) Mesoscale force.
D) Coriolis.
D) Coriolis.
Select the true statement from those listed below concerning jet streams:
A) Jet streams occur on the warm side of the frontal surface with their jet cores positioned just beneath the tropopause.
B) A jet stream located in or near the tropics is generally stronger that one that is present in the mid latitudes.
C) Extensive, dense cirrus cloud, when associated with a jet stream, is located on the cold air side of the jet core.
D) The cores of jet streams can usually be found just above the warm air tropopause.
A) Jet streams occur on the warm side of the frontal surface with their jet cores positioned just beneath the tropopause.
You would expect a north-to-south jet stream when:
A) The temperatures below the jet core are colder to the north than to the south.
B) The air beneath the jet stream is colder to the east than to the west.
C) The 200hPa contours are higher to the north than to the south.
The air is considerably warmer than ISA above the jet stream core.
B) The air beneath the jet stream is colder to the east than to the west.
Why do jet streams suddenly accelerate and decelerate?
A) Centrifugal forces around sharp ridges and troughs.
B) Changing pressure gradient forces along the earths surface.
C) Neither (A) or (B) are correct.
D) Both (A) and (B) are correct.
A) Centrifugal forces around sharp ridges and troughs.
There are several jet streams that affect the weather in Canada. How are they named?
A) Three of the jet streams are named after their under-lying front, and the fourth is called the Subtropical Jet stream, which is due to the circulation within the Hadley Cell located in the subtropics.
B) All of the jet streams are named after their underlying fronts.
C) The names are in honor of famous meteorologists.
D) Two of the jet streams are named after their underlying front, and the third is called the Subtropical Jet stream derived within the Hadley Cell.
A) Three of the jet streams are named after their under-lying front, and the fourth is called the Subtropical Jet stream, which is due to the circulation within the Hadley Cell located in the subtropics.
The height of the jet stream core that is located above the polar front is:
A) Lower than the jet stream core located above the arctic front.
B) Located at roughly the same height as the one above the arctic front.
C) Higher than the subtropical jet stream core.
D) Higher than the jet stream core located above the Arctic front.
D) Higher than the jet stream core located above the Arctic front.
One of the prime areas where CAT is found is in the vicinity of jet streams. Several statements relating to CAT and jet streams appear below. Identify those which are correct:
1) Severe CAT is likely to be present when the vertical wind shear associated with a jet stream attains a value of at least 2KT/1000 ft.
2) The threshold wind speed of a jet stream for the occurrence of CAT is approximately 90 KTs.
3) Curving jet streams are more likely to have turbulent edges than straight jet streams especially those which curve around a deep pressure trough.
4) The most severe CAT associated with a very fast moving jet stream is always located on the high pressure side of the jet stream core.
5) Wind shear and the accompanying CAT adjacent to jet streams are most intense above and to the lee side of mountain ranges.
6) The confluence of two jet streams can be a producer of CAT.
A) 1, 2, 3.
B) 2, 4, 6.
C) 3, 5, 6.
D) 1, 3, 5.
C) 3, 5, 6.
