Met General 200 Questions Flashcards
That part of the Earths atmosphère where most of the clouds and précipitation are Found is?
Troposphère
Statement with respect to the tropopause
- Lower over the pôles
- Higher over the equator
- Température at the tropopause is colder over the equator
The Height of the tropopause higner over ?
The equator: density of the air in this région is less and therefore Higher.
The Height of the tropopause Will tend to be Higher in?
-In warmer air mass
-When MSL pressure is high
Région of the atmosphère between stratopause and mesopause is?
Mesosphere
The Sun emits large amounts of ultraviolet radiation and is largely absorbed by a colorless gas that is found at varying amounts throughout the atmosphere. This gas is known as ?
Ozone
The earth’s surface is heated by?
Short wave solar (ultraviolet) radiation
What is the intertropicale convergence zone (ITCZ)
Is the area on the earth where solar radiation is at its strongest
Why does the ITCZ move south during winter months?
The northern hemisphere becomes titled away from the sun during winter meaning the point of maximum solar radiation striking the earth moves southward
The lower atmosphere is heated by?
-Conduction
-long wave solar (infrared) radiation
Temperature in the lower stratosphere approximate those?
Of the tropopause
In the international atmosphere (ISA) The temperature at sea level is 15°C and the pressure is 1013.2 hPa. What would be the ISA temperature for FL300
-45°
The actual temperature at FL280 IS -48°C. How would this temperature be expressed in terms of an ISA deviation?
ISA -7°C
If you are flying at 34 000’ with a SAT of -50°C and the tropopause was actually at 30 000’ where SAT was -51°C, what is the deviation from ISA?
You are flying at 38 000’ with a SAT of -50°C and the tropopause was actually at 44 000’ where SAT was -65°C, what is the deviation of ISA?
As air move horizontally over the earth in the N. Hemisphere, the air is deflected to the right. This is known as the Coriolis and it caused by the ?
Rotation of the earth
Where Coriolis is stronger?
Coriolis is stronger nearer to the poles
Vertical air currents are often created within the atmosphere by varying means. A process that will lead to rising air is known as ?
Convection
Where would experience the LEAST diurnal range in temperature?
Temperate zone oceans
True statement about warming
Convection is more likely to occur over water-free surfaces
The lifting process responsible for the choppy type of turbulence often encountered during flight within the lower 3000’of the troposphere is?
Mechanical turbulence
Lifting agent?
-Convection
-Mechanical turbulence
-Convergence
Meteorologists use the term convergence to detect air that is?
Flowing along the earth’s surface from areas of higher pressure into and converging at an area of lower pressure
Which processes can result in expansional cooling, subsequent condensation and formation of cloud?
Overrunning
Define overrunning?
It refers to how fast warm air rises vertically as it flows up along the frontal surface over the retreating cold air.
The clouds and precipitation often associated with a cyclone are due to?
Surface convergence and ascending air
What would be used to describe the process whereby a rising, expanding parcel of air does not undergo any heat transfer in or out the parcel as it ascends?
Adiabatic
Subsiding air, even if it is initially saturated, will?
Warm at the dry adiabatic lapse rate
With respect to air that is descending rapidly down the lee slopes of a mountain range?
This air will warm at the dry adiabatic lapse rate almost immediately after the start of its descent
When air side normally the relative humidity will?
The relative humidity decrease
When air ascends, its ability to contain moisture?
Decrease
During the condensation process?
Latent heat is released to the surrounding air
When condensation occurs in an unstable air mass, the stability of the air tends to become ?
More unstable as heat is released to the surrounding air
With a surface temperature of 28°C and a dewpoint temperature of 16°C reported at your airport, you would predict the base of any convective cloud that might form to be approximately:
4900’ AGL
With respect to a rising parcel of air which commences to ascend from a sea level airport where the temperature is 30°C, what would be its temperature at 14 000’ above sea level of its became saturated at 6000’ ASL.
+0°C
When discussing the stability/instability of the atmosphere, we are referring to:
A property of the atmosphere that suppresses or promote vertical motion
The stability of warm, dry air depends on the relationship between the?
Dry adiabatic lapse rate and the environmental lapse rate
Stable air is most likely to be associated with?
Sustained low visibility
Haze layers, drizzle and fog ares features of?
Stable air
One weather condition that may affect visibility in unstable air is?
Snow showers
Stable air becomes unstable as a result of?
Subsidence
A good signpost of mid-level instability would be the pressure of?
Altocumulus castellanus
What effectively inhibits or blocks rising air?
An inversion
The pilot of an aircraft would expect the smoothest low level flight during a hot summer afternoon when passing over what surface features?
A lake
A pressure of 200 hPa is closest to what levels in the ICAO standard atmosphere?
FL390
FL450 is associated with which pressure level in the ICAO standard atmosphere?
150 hPa
The vertical distance between any two specific pressure level is?
Less in cold air than in warm air
The height of a pressure level (ex: 500mb) will be tend to be found at?
A lower level in a colder air mass
The height of a pressure level will?
Become lower when a low is deepening
Flying in the lower levels towards the center of an anticyclone which has a strong pressure gradient, a pilot would expect?
High winds
Increasing barometric pressure
When flying towards a ridge of high pressure at FL200, what happens to the height of the pressure level and your true altitude?
Pressure level goes up and your true altitude goes up
When flying at FL200 towards an area of colder air on the surface of the earth, what happens to the height of the pressure level and your true altitude?
Pressure level goes down and your true altitude goes down
When flying at FL370 towards a ridge of high pressure and an area of warmer air on the surface of the earth, what happens to your indicated altitude (shown on your altimeter) and your true altitude?
Indicated altitude stays the same, but your true altitude goes up
An aircraft is parked on the apron. You go home for the night. During the evening, cold air moves into the vicinity of the airport. When you return to your aircraft in the morning, what does the altimeter show?
There will be no change in the altimeter’s reading
What statement relating to an anticyclone is true ?
-Fair weather and clear skies normally prevail within the region of an anticyclone
-an anticyclone is generally characterized by a downward vertical movement
-anticyclones can be described as strong or weak and strengthening or weakening
Surface highs and lows develop as a result of ?
Upper level convergence and divergence forcing air to sink or rise respectively
A trough is?
An elongated area of relatively low atmospheric pressure
A neutral area, not bounded by any one isobar, within which light winds are blowing and the weather is changing very slowly, exists between two high and two low pressure systems. The name given to this indefinite pressure area is?
A col
During descent from 3000’ AGL to the surface, you would expect the wind to?
Back and decrease
The wind at 3000’ over the land is parallel to the isobar at 30kt. What would be the most probable angle to the isobar and speed of the surface wind assuming it is not affected by local topography?
30° / 20kt
Given the same pressure gradient over the land and over the adjacent water, what is the most probable wind angle to the isobars and wind speed over the water if the surface wind over the land is blowing across the isobars at an angle of 30° and at a speed of 30kt?
20° / 40kt
A flight from Vancouver to Montreal at a constant pressure level experiences winds that gradually veer from the southwest to the northwest. The aircraft’s actual height above mean sea level will have: (hint: port drift -A/C true altitude is increasing; starboard drift A/C true altitude is decreasing)
Increased for a time and then decreased steadily thereafter
If the temperatures to the southwest today are warmer than those to the Northwest, the winds aloft would be blowing from the: (recall buys-ballots law - with your back to the wind, your left hand will point to the area of the lower pressure; for upper level winds, your left hand will point to area of lower temperatures…)
Southwest
What relate to density altitude?
-The density altitude is that altitude in the standard atmosphere which corresponds to a given density value.
-An increase in density altitude corresponds to a decrease in density.
-The density altitude for a given aerodrome is changing continually in response to changes in pressure and temperature.
An aerodrome’s density altitude is calculated with a flight computer using the?
The aerodrome’s pressure altitude matched with the aerodrome’s outside air temperature correct in terms of ASL
An aircraft’s true altitude would be greater than its indicated altitude in conditions of ?
Warm air and high pressure
What statements is true with respect to the term MSL pressure?
Is is station pressure reduced to MSL using the average surface temperature for the last 12h.
Altimeter setting is?
Station level pressure reduced to MSL assuming ISA conditions
It is essential that a pilot flying in the standard pressure region closely monitor terrain clearance, when:
Pressure and temperature are low
An aircraft descends from FL380 for an approach to the Kelowna airport. During the descent, the pilot forgets to reset the altimeter subscale. If the published decision height (DH) is 2060’ ASL, what would be the actual height of the aircraft on reaching the indicated DH?
METAR CYLW 281700Z 18010KT 5SN-SHRA OVC015 10/06 A2962 RMK SF8 SLP150
1760’ ASL
Compare two aircraft on approach - the 1st aircraft is flying the approach in standard atmospheric conditions; the 2nd aircraft in colder than standard conditions. Both aircraft arrive over the final approach point/fix at the altitude that is shown on the approach plate (to temps correction) what is the second aircraft’s altimeter reading in relation to the first, and what is the results?
The second aircraft’s altimeter will be over-reading, and therefore the aircraft will be lower than the published altitude.
Aircraft in colder than standard conditions. On an RNAV/RNP approach. What will happen to the slope of the approach flown by the aircraft?
The aircraft will fly a shallower approach path and touchdown with zero temperature error on the altimeter.
The relationship between the amount of water vapor actually present in the air and the maximum possible amount of water vapor that could be held by the air at that temperature and pressure (without condensation occuring) is expressed by what?
Relative humidity
The height of a cloud base is most dependent upon the ?
Moisture content of the air
Clouds and precipitation are common in areas?
Of ascending air
What type of cloud frequently forms as a result of evaporation from rain rather than from expansional cooling?
Stratus cloud
If the air mass is moist and stable with mechanical turbulence present in the lower levels, what type of clouds can you expect to be present?
Stratus et stratocumulus cloud
Rain droplets or snowflakes that fall from cumuliform cloud and evaporate or sublimate before reaching the ground is called?
Virga
Flying through or underneath virga usually results in?
Chopping flying conditions due the cooling effect as water droplets evaporate back into a gaseous state causing the more dense air to sink rapidly creating a form of wind shear
Drizzle forms through the ?
Condensation and coalescence processes occuring in Stratus cloud
Snow falling from a layer of stratocumulus cloud would indicate that
The liquid water content in the cloud is decreasing?
An airport weather observer reports snow grains; this type of precipitation would imply:
The freezing drizzle is present aloft
A large area of land or ocean of relatively uniform characteristics and above which an air mass can form, is known as a ?
Source region
A true statement with respect to air masses would be?
Air masses are classified according to their moisture content
When continental arctic (cA) air moves southbound over the Great Lakes during the winter you would expect:
Snow showers immediately to the south of the southern shorelines
What would you expect to occur when maritime tropical (mT) air moves northwards over the Great Lakes in the spring and early summer?
Low Stratus cloud, drizzle and fog over the north shores.
As continental arctic (cA) air moves southbound over the Great Lakes in early autumn, it often produces ?
Steam fog over the northern portions of the lakes
Fronts are named according to ?
The colder air mass and it’s direction of movement
What warm fronts would most likely be present on Canadian weather charts during the winter months?
Continental arctic and maritime arctic
As you fly towards a warm front share the warm air is moist and unstable, the sequence of clouds that you would expect to encounter would be?
CI, CS, AS, NS and embedded CB’s
The extensive stratiform cloud decks commonly associated with warm fronts are caused by?
Expansional cooling of the overrunning warm air
During flight in the lower levels toward a warm front, you notice that the precipitation changes from steady rain to heavy showers. You would then assume that?
The warm air was moist and unstable
As you fly in the lower levels of the cold air mass side toward a winter warm front (mA air overrunning cA air), you encounter ice pellets. In this case, you would know that there was?
Freezing rain above
What cold fronts are likely to be found on Canada during the summer months?
Maritime arctic & maritime polar
Cold frontal weather is determined by?
-The stability of the warm air mass
-The moisture content of the warm air mass
-The speed of the front and the steepness of its frontal surface
The cloud and precipitation associated with a cold front develop because?
The warm air that is lifted up the frontal surface cools by expansion
A rapidly moving cold front with a steep frontal surface has moved into your region. You more however, that no extensive areas of convective cloud have formed along the front. This would indicate?
The warm air mass has a low relative humidity
An approaching cold front that initially has a shallow frontal surface, steepens some distance behind the surface front. You experience a wind shift and a drop in temperature, when would you expect clouds and precipitation to occur?
Will occur later
You are at an airport that experience the passage of a cold front in the early afternoon. Shortly afterwards, the clouds scatter out leaving a clear sky. During the next 12h, you would expect temperature to ?
Increase slightly then decrease
A cold front with a steep frontal surface that is advancing rapidly upon moist, unstable air produces a suitable environment for ?
A squall line of thunderstorms
A combination of both cold front and warm front weather conditions would most likely be associated with which of the fallowing?
- An occluded front
- A trowal
In the northern hemisphere, the future movement of a mature frontal depression and its associated frontal wave will tend to be parallel to the ?
Warm sector isobars
At a stationary front, the cold air moves?
Parallel to the front
The transition zone between 2 different air masses where there is a sudden change in temperature and moisture content is called?
A front
When the properties of 2 air masses along a front are becoming increasing different in temperature and moisture, it is referred to as what?
Frontogenesis
A land breeze?
Blows from the land to the water during night
A condition favourable for the development a strong Katabatic winds would be?
A region of extensive glaciers
A warm Katabatic wind found in very hilly terrain is known as a ?
Chinook wind
Anabatic winds can best be characterized as ?
Upslope winds that develop on mountain slopes as they are heated by the sun
An aircraft flies over an airport on radar vectors for an approach. The pilot notes that she can see the airport through a thin layer of fog. What can the pilot foresee as she turns onto final approach?
The airport will not be clearly seen since slant range visibility will be less.
What adds to a whiteout illusion (no depth perception) besides a snow covered surface?
Uniformly overcast sky
The requirement for the formation of all types of fog is?
High relative humidity
A south-westerly flow of mT air moving over the Labrador current would produce?
Advection fog
What best describes the fog that would develop as the air flows from the Pacific ocean towards the Rockies?
Upslope fog
The fog that forms ahead of a warm front is the results of?
The evaporation of rain as it falls from the warm air into the cold air below
What cooling processes is involved in the formation of the fog that frequently follows a warm front?
Advection
What types of fog forms as a result of raising the dewpoint up to the outside air temperature?
Steam fog
Artic sea smoke
Frontal fog
Steam fog forms when?
Water evaporates into very cold air in contact with it
When very cold, dry air drifts across the relatively warm waters of lakes, streams or marsh surfaces during cold autumn mornings, you would expect the formation of ?
Steam fog
Both Steam and radiation fog require what for the formation?
Condensation nuclei
What conditions are favourable for the production of radiation fog?
High relative humidity
The presence of industrial smoke
Light winds (2-5kt)
The presence of an anticyclone
Radiation fog does not form over the ocean surface since ?
This surface does not cool by radiation at night
The development of radiation fog can be aided by?
The presence of industrial smoke
When comparing advection to radiation fog, you would know that?
Advection fog can form over both water and land, whereas radiation fog forms only over the land
Adiabatic cooling causes what types of fog to form?
Upslope fog
When moist air moves from east to west across the Prairies youl would expect what to occur?
Widespread upslope fog increasing toward the foothills of the Rocky mountains
The physical process involved in the formation of ice fog is?
Sublimation
During the spring, what is the name of the air mass and the associated front that can lead to advection fog occuring in the vicinity of South Western Ontario?
Maritime tropical & Polar front
When temperature are very low, a jet aircraft that takes off from a northern airport can trigger the formation of which of the following types of fog?
Ice fog
With respect to airframe icing, which factors determine the rate of catch?
-Supercooled water droplet size
-The number of supercooled water droplets present
-aircraft speed
-shape of the aircraft wing
Large supercooled water droplets are most likely to be found in the ?
Lower levels of cloud that as formed in unstable air where temperatures are only a few degrees below
If you inadvertently flew through a TCU of CB, you would expect moderate to severe icing down to what temperature?
-25°C with light icing down to temperatures of approximately -40°C
You would expect that rime ice accumulation rather than mixed or clear ice accumulation would occur when the rate of catch is ?
Low and droplets are small
During an IFR cross country flight, your aircraft has been encountering light to moderate mixed icing. You notice that an increasing number of ice crystals are beginning to form within the cloud and would, therefore, expect that the further accumulation type and intensity would change ?
Rime icing and decreasing intensity
The shadow of the wing is an important factor in determining it’s collection efficiency. When comparing a thin wing to a thick wing traveling at the same airspeed, it can be demonstrated that the leading edge of a thin wing will collect?
More ice per square inch
With respect to airborne icing, the collection efficiency of a wing would be increased with?
Thin leading edges, high speeds and large droplets.
There is considerable variation in the liquid water content in the vertical of a cloud that has been formed in stable air. In fact, the amount of supercooled water droplets in this type of could usually?
Increases with height when temperatures are not far below freezing.
What statements is true with respect to freezing drizzle?
Icing in freezing drizzle is at its worst near the base of the cloud
Freezing rain occurs when?
Rain falls into a sub-freezing layer of air
Rime ice forms when ?
Supercooled water droplets freeze almost instantaneously without spreading
Water droplets instead of ice crystals (IC) exist within the atmosphere at temperatures down to approximately -10°C due to the fact that?
Ice nuclei are not present until temperatures drop below -10°C
Ice nuclei are important in the formation of snowflakes because it allows?
The water vapour molecules to sublimate onto the IC in a crystalline format
What phenomena could accumulate a deposit of rime ice on its wings?
Freezing fog
If a METAR is reporting snow grains (SG) or Snow pellets (GS), what does this indicate to you?
Some type and intensity of airframe icing will be experienced in either situation due to supercooled water droplets present in the cloud above.
Supercooled rain that freezes while falling through a sub-freezing layer becomes:
Ice pellets
Snowflakes that receive a coating of rime ice as it’s falls through a layer of supercooled water droplets and reaches the earth’s surface will reported?
Snow pellets
Drizzle that falls through a below-freezing layer and freezes before reaching the earth’s surface will be reported as?
Snow grains
Aggregation refers to?
The growth of snowflakes as they collide together forming larger snowflakes.
The term used to describe the growth of a descending ice particle as it collides with nearby water droplets which the freeze onto the particle is ?
Riming
You have just landed after completing a flight at high altitude lasting for several hours. You are to make station stop lasting about 30min to pickup some passengers before departing without taking on any further fuel. There is light wet snow falling at the airport with temperature of +3°C. How and when would you check for surface contamination?
Tactile feel just prior to closing the cabin door as you will be unable to determine visually if the melted snow has refrozen or not.
The formation of clear ice on an aircraft is due to ?
Relatively large supercooled water droplets striking the airframe at a high catch rate which slowly freeze allowing the droplets to spread rearwards before freezing entirely
Can you T/O with frost on the underside of the wing?
Yes as long as it doesn’t exceed the aircraft manufacturers recommandations.
What statements relating to the effects of aerodynamic heating of an airfoil in overall icing conditions is true?
An airspeed of at least 500kt is required to ensure no ice will collect
As well as a lifting force or triggering action, the other conditions necessary for the formation of a well-developed thunderstorm are ?
An abundant supply of moisture and a steep lapse rate.
The commencement of the dissipating stage of a storm cell is characterized by?
The downdrafts encompassing the entire cell horizontally
Flight beneath the anvil cloud of a thunderstorm cell should be avoided due to ?
The serious hazard of encountering hail that has been thrown out of this overhanging cloud by the strong upper wind flow.
At what stage of development of a thunderstorm cell would the most serious icing problem be present ?
Just before the cell enters the mature stage
Mammatus clouds are frequently associated with?
Violent thunderstorm and tornadoes
What is the name given to a low-level, tube-shaped, detached cloud that is frequently observed on the leading edge side along a line of strong cumulonimbus clouds?
Roll cloud
Funnel clouds can form as cone-shaped columns or protuberance extending downwards from the main cloud base of a towering cumulus or cumulonimbus cloud. What statements can we make relating to funnel clouds?
-A funnel cloud is a vortex of condensed water vapor and air spinning at high velocity.
-If a funnel cloud is in contact with the ground, then it becomes a tornado.
-If a debris swirl is present on the ground underneath a funnel cloud, the meteorologists classify it as a tornado.
Meteorologists involved with the forecasting of severe weather phenomena would agree that one of the identifiable features associated with tornado development would be ?
Mesocyclonic movement detected by high-resolution Doppler radars.
The recommended technique following the inadvertent penetration of a thunderstorm cell is?
Slow to turbulence penetration speed. Do not attempt to maintain a rigid altitude or airspeed and maintain present heading.
An echo that has a distinct hook depicted on an aircraft’s weather radar could be a sign of what?
Tornado
What distance should thunderstorms be avoided by?
5nm when below the freezing level
10nm when above the freezing level
20nm when reported as severe
When should you scan a thunderstorm with your weather radar ?
Start in mid levels and then below
The amount of energy that is returned to the weather radar antenna is dependent upon 3 factors:
-The type of the precipitation
-The concentrations of the precipitation
-The water droplets size
Which one is more important?
The water droplets size
What is an advantage of a storm scope over a weather radar set?
-Not subject to the same amount of attenuation
-At lower altitudes, it will detect possible thunderstorm around higher terrain
-If tends to be a lower cost item
What is attenuation with respect to an aircraft’s weather radar?
-A radar signal degrades with distance
-one area of heavy rain blocks out other areas of rain in behind the 1st.
Describe characteristics of a downburst:
-Downbursts can be described in terms of size as being “micro” or “macro”
-Downbursts are colder than the surrounding air due to the cooling process as the rain droplets partially evaporate as they descend to the ground.
- due to the evaporational cooling effect, the air accelerates downwards increasing the severity of the downburst.
-A downburst can create both an increased performance shear and/or decreased performance shear situation for an aircraft on approach of during T/O
What could the term “Virga” imply in a METAR?
Microburst
The shaft of a microburst at the surface is normally about ________ wide?
2.2nm or less
A large change in wind direction or speed over a short distance is known as ?
Wind shear
A condition or phenomenon associated with potentially dangerous wind shear, especially during T/O and landing, would be?
A low level temperature inversion (with strong winds above the inversion)
With respect to low level nocturnal jet streams, what statements are true?
-They occur mostly in summer
-They generally form over flat terrain during the presence of southwest winds
-They are usually associated with temperature inversion
There is a low level frontal jet stream (LLJ) located?
Parallel to the cold front in the warm sector of the frontal wave
Where is the CAT associated with the LLJ located ?
About 1-3h prior to the passage of the cold front
When are LLJ depicted in GFA?
-When the core speed is expected to be 50kt or more
-When the jet core is located within 6000’ASL, except as required over higher terrain
-The height of the jet is not indicated
A pilot taxiing an aeroplane for T/O notes that rain is falling from the base of a convective cloud that is located relatively high above the ground but is evaporating before it reaches the ground. He/she should be aware that this occurence could signal the presence of ?
A dry microburst
What statements is true in reference to “dry” microburst?
-They can often be identified by the presence of “virga”
-They are linked with high-based cumulus and Altocumulus type clouds
-with this type of microburst, evaporative cooling intensifies the downdrafts
Downdrafts associated with microburst could be as strong as?
6000’/min
Localized meteorological conditions that produce intense wind shears at Arctic airports ad well as at airports situated along the coasts of Canada’s mountainous regions could be due to the presence of ?
Valley
Katabatic
Funnel winds
One of the signposts for the existence of a mountain wave is ?
The presence of Altocumulus standing lenticular clouds
The lowest group of stationary clouds associated with a mountain wave is ?
Rotor cloud
Rotar clouds found during mountain wave activity are located?
-Located at the ridge top heights with their bases often extending below
-Beneath the wave crests within the mountain wave
Where are lenticular clouds located in a mountain wave?
At the wave crest
The most powerful rotor associated with the presence of a mountain wave is located?
In the proximity of the first wave crest
The part of a mountain wave system that usually presents the most severe turbulence is located?
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?
There is a jet stream wind aloft that is oriented perpendicular to the axis of the mountain range
What statements is correct with reference to a mountain wave system?
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 occurence of?
An abrupt change in the temperature lapse rate
The tropopause definition?
Acts as a lid on the clouds and weather of the troposphere
There is an abrupt change on the height of the tropopause over each?
Frontal surface
What air masses would most likely have the highest tropopause height
mT maritime tropical
The tropopause is ?
Higher and colder over warm air mass
With respect to the tropopause, what is a true statement?
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 it’s temperature are specified as ?
36 089’
-56,5°C
What causes jet streams to form?
-A strong pressure gradient force that is derived from a strong temperature contrast on the earth’s surface that upsets the height of the pressure levels.
-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
Along with presence of steep horizontal pressure gradients, what constitutes a major factor in the formation of jet streams?
Coriolis
A true statement concerning jet streams?
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 flow when?
The air beneath the jet stream is colder to the east than to the west
Why do jet streams suddenly accelerate and decelerate?
Centrifugal forces around sharp ridges and troughs
There are several jet streams that affect the weather in Canada. How are they named?
Three of the jet streams are named after their under-lying front and the fourth is called the subtropical jetstream, 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?
Higher than the jet stream core located above the arctic front
One of the prime areas where CAT (clear air turbulence) is found is in the vicinity of jet streams. Several statements relating to CAT and jet streams are correct?
The directional changes that occur as very fast, high level winds flow around upper lever throughs and ridges can the result in the development of CAT. What statement best describes the shear and resulting turbulence that can be expected with such mesocale features.
Turbulence associated with upper level throughs tends to be more severe than with upper level ridges.
The vertical extent of clear air turbulence associated with a jet stream will be the greatest on the ________ side of the jet stream core.
Low pressure, Cold air mass
While flying across a jet stream in North America, an aeroplane encounters some CAT. The pilot checks the OAT gauge and notes a temperature rise. To quickly escape from the turbulence, he/she should?
Climb the aeroplane
What statements is true with respect to the Polar Jet stream?
This jet stream moves south during the winter and generally has higher core speeds than in the summer.
Jet streams having speeds above _____kt_ At the core will have areas of significant turbulence near them in the sloping tropopause above the core, in the jet stream front below the core and on the cold air (low pressure) side of the core.
110kt
Flying near a jet stream in a crosswind situation and encountering moderate CAT, the pilot checks at the OAT and notes that it remains constant. In this case, in order to escape from the turbulence, the pilot should?
Either climb or descend the aircraft
CAT is also related to vertical wind shear, so when the shear is greater than____kts/1000ft, turbulence is likely.
5kt
