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Question 157-1 : Where is the most dangerous zone in a tropical revolving storm ? [ MCQ aircraft ]

In the wall of clouds around the eye

exemple 257 In the wall of clouds around the eye.

Question 157-2 : In the month of august you prepare a flight cruising level fl 370 from bombay 19°n 73°e to bangkok 13°n 100°e what wind conditions can you expect ?

Headwinds

Admin . 535.you will face the tropical easterly jet at fl370 exemple 261 Headwinds.

Question 157-3 : Tropical revolving storms do not occur in the southeast pacific and the south atlantic mainly because ?

Of the low water temperature

Admin .by elimination .there is no coriolis force at the equator only the coriolis force varies with latitudes . 566.in the southeast pacific the wind comes from nw the 'westerlies' . 596.se trade winds cross over into the northern hemisphere only between dakar and indian ocean up to the philippines . 2537.in the end tropical revolving storms do not occur in the southeast pacific and the south atlantic mainly because of the low water temperature exemple 265 Of the low water temperature.

Question 157-4 : What is the main energy source of a tropical revolving storm ?

Latent heat released from condensing water vapour

exemple 269 Latent heat released from condensing water vapour.

Question 157-5 : During july flights from bangkok 13°n 100°e to karachi 25°n 67°e experience an average tailwind component of 22 kt in january the same flights also operating at fl 370 have an average headwind of 50 kt .what is the reason for this difference ?

The wind components correspond to the seasonal change of the regional wind system

.in july the tropical easterly jet at fl370 will push you sw monsoon from bangkok to karachi in january you will face the subtropical jet during the winter months in the northern hemisphere the polar front pushes farther southward because of the greater density of the polar air than during the summer months exemple 273 The wind components correspond to the seasonal change of the regional wind system.

Question 157-6 : Which typical weather condition is shown by the design for the area of central europe . 315 ?

Westerly waves

Admin .a series of fronts or depressions one after the other is referred to as a westerly wave over central euopre .these systems move in the direction of the first two isobars in the warm sector which tend to be straight and parallel when the cold and warm fronts begin to occlude the direction of movement is increasingly towards the pole exemple 277 Westerly waves.

Question 157-7 : Which typical weather condition is shown by the design for northern italy . 316 ?

High pressure

Admin .as we can see an anticyclone is located over italy exemple 281 High pressure.

Question 157-8 : The attached chart shows the weather conditions on the ground at 1200 utc on october 10 which of the following reports reflects weather development at zurich airport . 317 ?

Taf lszh 101500z 1016/1101 vrb02kt 8000 nsc becmg 1016/1018 3500 mifg becmg 1018/1020 1500 bcfg becmg 1020/1022 0100 fg vv001=

Admin .we have a large flat pressure pattern an area with light or no wind zurich has therefore the lowest probability of precipitation .radiation fog will occur at night .radiation fog is formed by the cooling of land after sunset by thermal radiation in calm conditions with clear sky .no change in wind condition is expected for the next hours since the isohypses are well spaced exemple 285 Taf lszh 101500z 1016/1101 vrb02kt 8000 nsc becmg 1016/1018 3500 mifg becmg 1018/1020 1500 bcfg becmg 1020/1022 0100 fg vv001=

Question 157-9 : You are flying from east to west in the northern hemisphere at the 500 hpa pressure surface which of the following statements is correct ?

If the wind is from the north you are gaining altitude

Admin .if you stand with your back to the wind in the northern hemisphere low pressure is on your left buys ballot's law . 562.you are flying toward a high you are gaining altitude exemple 289 If the wind is from the north you are gaining altitude.

Question 157-10 : Divergence in the upper air results near the surface in ?

Falling pressure and likely formation of clouds

Admin . 563.divergence in the upper air means convergence on the ground this a low pressure area and clouds may appears above it exemple 293 Falling pressure and likely formation of clouds.

Question 157-11 : In a low pressure system the convergence at the surface is caused by ?

Frictional forces

Admin . 498.at the surface and at low elevations friction will slow the air and hence the coriolis will be less effective in its deflection of the wind .the flow turns across the isobars you have more flow into the low pressure system giving convergence and feeding the convection exemple 297 Frictional forces.

Question 157-12 : If the pressure surfaces bulge upwards in all levels then the pressure system is a ?

Warm high

Admin .if isobars bulge up in all level you have a high pressure at the surface and high temperatures in the air exemple 301 Warm high.

Question 157-13 : A cold air pool ?

Is usually most evident in the circulation and temperature fields of the middle troposphere and may show little or no sign on a surface chart

exemple 305 Is usually most evident in the circulation and temperature fields of the middle troposphere and may show little or no sign on a surface chart

Question 157-14 : The stable layer at some height in the low troposphere of an older high pressure area in the mid latitudes is called ?

Subsidence inversion

Admin .as the upper air sinks older high pressure subsides it warms . 570.this can lead to warmer air in the mid troposphere than at the surface this phenomenon is called subsidence inversion exemple 309 Subsidence inversion.

Question 157-15 : A blocking anticyclone in the northern hemisphere is ?

A warm anticyclone quasi stationary situated between 50°n and 70°n

Admin .the blocking anticyclones in the northern hemisphere are over the oceans these are parts of the belt of sub tropical high pressure formed over relatively warm ocean surfaces .they block the path of atlantic depressions exemple 313 A warm anticyclone, quasi stationary, situated between 50°n and 70°n.

Question 157-16 : Which statement is true for hurricanes in the north atlantic ?

From the earth's surface up to the tropopause the core is warmer than its surroundings

exemple 317 From the earth's surface up to the tropopause the core is warmer than its surroundings.

Question 157-17 : Assume that an aircraft is flying in the northern hemisphere at the 500 hpa pressure surface on a heading of 270 degrees .which of the following statements is correct ?

If in this pressure surface the wind comes from the direction 360 degrees then true altitude is increasing

Admin .if you stand with your back to the wind in the northern hemisphere low pressure is on your left .with a wind coming from the direction 360 degrees and you stand with your back to it low pressure is on the east .on a heading of 270 degrees we are flying towards high pressure thus true altitude is increasing exemple 321 If in this pressure surface the wind comes from the direction 360 degrees, then true altitude is increasing.

Question 157-18 : An aircraft is flying at fl 180 in the northern hemisphere with a crosswind from the left which of the following is correct concerning its true altitude ?

It decreases

Admin .if you stand with your back to the wind in the northern hemisphere low pressure is on your left buys ballot's law . 573.with a crosswind to the left must mean you are heading into an area with a lower temperature our true altitude decreases exemple 325 It decreases.

Question 157-19 : Which of the following is true concerning an aircraft that is flying at fl180 in the northern hemisphere where wind is geostrophic and the true altitude remains constant ?

There is no cross wind

Admin .we have a geostrophic wind when the pressure gradient force pgf is exactly balanced by coriolis force . 582.it is only happens when isobars are straights and parallels .if there is no change in your true altitude you are flying along the isobars so you will have a headwind or a tailwind but no crosswind exemple 329 There is no cross wind.

Question 157-20 : The reason for the fact that the atmospheric pressure of a polar front depression is normally lower in winter than in summer is that ?

The temperature contrasts between arctic and equatorial areas are much greater in winter

Admin .the warm air is fairly consistent throughout the year but the cold air is much colder in the winter exemple 333 The temperature contrasts between arctic and equatorial areas are much greater in winter.

Question 157-21 : In which of the following areas do surface high pressure systems usually predominate over the north atlantic region between 30°n and 65°n and the adjoining land areas during the northern summer ?

Azores se usa sw europe

Admin .from winter to summer the polar front over the north atlantic moves towards the north . 598.between 30°n and 65°n in winter . low pressure systems centered over iceland / greenland . high pressure systems centered over azores siberia . the polar front extends from florida to sw england .between 30°n and 65°n in summer . low pressure systems centered over ne canada . high pressure systems centered over azores se usa sw europe . the polar front extends from newfoundland to n scotland exemple 337 Azores, se usa, sw europe.

Question 157-22 : In the northern hemisphere with an anticyclonic pressure system the geostrophic wind at 2000 ft over the sea is 350°/24 kt .at the same position the surface wind is most likely to be ?

340°/20 kt

Admin .values to be used in examinations .over sea wind speed in friction layer decrease by 30% the wind in the friction layer blows across the isobars towards the low pressure angle between wind direction and isobars changes by 10°.over land wind speed in friction layer decrease by 50% the wind in the friction layer blows across the isobars towards the low pressure angle between wind direction and isobars changes by 30° .the wind blows parallel to the isobars and in the northern hemisphere the surface wind will back and slowdown compared to it exemple 341 340°/20 kt.

Question 157-23 : Select the answer which you consider will complete correctly the following statement in relation to the main pressure systems affecting the north atlantic region between 30°n and 65°n .during winter the predominant mean low pressure system at the surface ?

Iceland / greenland

Admin .from summer to winter the polar front over the north atlantic moves towards the south . 585.between 30°n and 65°n in winter . low pressure systems centered over iceland / greenland . high pressure systems centered over azores siberia . the polar front extends from florida to sw england .between 30°n and 65°n in summer . low pressure systems centered over ne canada . high pressure systems centered over azores se usa sw europe . the polar front extends from newfoundland to n scotland exemple 345 Iceland / greenland.

Question 157-24 : The pressure system at position 'd' is . 319 ?

A col

Admin .a col is an area of almost uniform pressure between two highs and two lows no isobars define its boundary . 586 exemple 349 A col.

Question 157-25 : Considering the north atlantic region between 30°n and 65°n and the adjacent land areas during mid summer the predominant pressure systems are ?

Azores high and weak low over ne canada

Admin .from winter to summer the polar front over the north atlantic moves towards the north . 598.between 30°n and 65°n in winter . low pressure systems centered over iceland / greenland . high pressure systems centered over azores siberia . the polar front extends from florida to sw england .between 30°n and 65°n in summer . low pressure systems centered over ne canada . high pressure systems centered over azores se usa sw europe . the polar front extends from newfoundland to n scotland exemple 353 Azores high and weak low over ne canada.

Question 157-26 : Considering the north atlantic region between 30°n and 65°n together with the adjacent land areas during winter the normal disposition of the main anticyclones at the surface is ?

Azores siberia

Admin .from summer to winter the polar front over the north atlantic moves towards the south . 585.between 30°n and 65°n in winter . low pressure systems centered over iceland / greenland . high pressure systems centered over azores siberia . the polar front extends from florida to sw england .between 30°n and 65°n in summer . low pressure systems centered over ne canada . high pressure systems centered over azores se usa sw europe . the polar front extends from newfoundland to n scotland exemple 357 Azores, siberia.

Question 157-27 : The arrows labelled 'r' represent the mean tracks of tropical revolving storms which occur mainly from . 320 ?

December to april and are called cyclones

exemple 361 December to april and are called cyclones

Question 157-28 : Which is true of a secondary depression in the northern hemisphere ?

It tends to move round the primary in a cyclonic sense

Admin .wave depressions can grow off the tail ends of primary cold fronts the depression so formed is then called a secondary depression . 587.this smaller secondary depression moves around the main depression anti clockwise in the northern hemisphere and clockwise in the southern hemisphere .'cyclonic sense' = cyclone = low = counter clockwise exemple 365 It tends to move round the primary in a cyclonic sense.

Question 157-29 : The arrows labelled 's' represent the mean tracks of tropical revolving storms which occur mainly from . 320 ?

May to november and are called cyclones

Admin . 588 exemple 369 May to november and are called cyclones.

Question 157-30 : The arrows labelled 't' represents the mean track of tropical revolving storms which occur mainly from . 320 ?

June to october and are called cyclones

Admin . 588 exemple 373 June to october and are called cyclones.

Question 157-31 : The arrows labelled 'u' represent the tracks of tropical revolving storms which occur mainly from . 320 ?

July to october and are called typhoons

Admin . 588 exemple 377 July to october and are called typhoons.

Question 157-32 : When if at all is a tropical revolving storm most likely to affect darwin on the central north coast of australia ?

December to april

.the formation of tropical revolving storms requires high sea surface temperatures 26°c or more and these will occur at and just after the passage of the itcz the itcz reaches its most southerly position in january . 593.red lines show the maximum extreme positions .the peak season for southern hemisphere tropical revolving storms is december to april exemple 381 December to april.

Question 157-33 : A trough of low pressure on a surface synoptic chart is an area of ?

Convergence and widespread ascent

Admin .a pressure system in which the isobars around a low pressure become elongated such that the pressure is lower along the axes of the trough than on its two sides sometimes the isobars at a trough have a pronounced v shape active weather fronts always lie in troughs but not all troughs are frontal . 594.the air in the centre of a low pressure centre trough or heat trough is lifted by convergence and widespread ascent as is the air in the intertropical convergence zone exemple 385 Convergence and widespread ascent.

Question 157-34 : Which is true of a typical non frontal thermal depression ?

It forms over land in summer

Admin .the ocean surface temperature changes are relatively small between summer and winter .in winter cold land creates subsidence and increasing surface pressure .in summer the land warms causing convective lifting divergence at altitude and falling surface pressure non frontal thermal depressions form over land in summer exemple 389 It forms over land in summer.

Question 157-35 : During summer an anticyclone covers the british isles giving mainly clear skies .at 0600 utc a south coast airfield in southern england reports a surface wind of 350/06 .the coastline at the airfield perimeter is aligned in an east/west direction .during the next twelve hours the surface wind is ?

Become southerly to southwesterly and increase in velocity by afternoon

Admin .here is the situation . 599.we have a northerly land breeze during the night land is cold sea is warm . 600.during the day as the land heats up we are in summer the situation reverses and the wind will blow from the sea sea breeze from the south . 601.as we are in northern hemisphere the coriolis force will tend to turn it westerly exemple 393 Become southerly to southwesterly and increase in velocity by afternoon.

Question 157-36 : During summer a weak pressure gradient covers a coastal airfield in eastern england resulting in mainly clear skies .the surface wind at dawn was calm .if the alignment of the coastline in the vicinity of the airfield is predominantly north/south the surface wind direction is likely to become ?

Easterly to southeasterly and increase in velocitiy by afternoon

Admin .during a sunny summer day sea breeze is likely to occur . 601.this will initially be an easterly from sea to land and as it increases in strength during the afternoon coriolis will deflect it to the right in the northern hemisphere and it will become a southeasterly exemple 397 Easterly to southeasterly and increase in velocitiy by afternoon.

Question 157-37 : For the same horizontal distance between adjacent isobars the gradient wind speed will be least at ?

50°n with a cyclonic circulation

Admin .first of all you have to uinderstand that the effect of the coriolis force varies with latitudes . 566.with the curvatures of the isobars centrifugal force is introduced and always tries to throw the parcel of air outwards from the centre of its rotation and the resulting movement of air is called the gradient wind . green arrow = pgf pressure gradient force . red arrow = coriolis force . 583.with an area of high pressure anticyclone the centrifugal force is acting in the same direction as pgf effectively increasing it coriolis balances the total force pgf + centrifugal force and the gradient wind is 'high round a high' i e for a given gap between the isobars the gradient wind is stronger than the geostrophic wind .with an area of low pressure cyclonic circulation the centrifugal force is opposing the pgf effectively decreasing it coriolis balances the total force pgf centrifugal force and the gradient wind is 'low round a low' i e for a given gap between the isobars the gradient wind is weaker than the geostrophic wind .for a given space between the isobars given pressure gradient you will get the least wind speed around a low cyclonic circulation at high latitude exemple 401 50°n with a cyclonic circulation.

Question 157-38 : Over which areas can tropical cyclones occur ?

Caribbean sea gulf of bengal indian ocean east of madagascar

Admin .no tropical cyclones over lands neither over cold water such as north atlantic or oriental pacific .cyclone from greek 'kuklos' means 'circle' is a generic term for all tropical revolving storms according to the geographical location the terminology differs . cylcone in the south western and northern pacific ocean and the south western indian ocean . hurricane as derived from huracàn a taino and carib god or hunraken the mayan storm in the northern atlantic ocean and the north eastern and south western pacific ocean east of 160e . typhoon from chinese t'ai fung located in in the north western pacific ocean . 603. caribbean sea gulf of bengal indian ocean east of madagascar is the only valid answer exemple 405 Caribbean sea, gulf of bengal, indian ocean east of madagascar.

Question 157-39 : The hurricane season in the caribbean is mainly from ?

July until november

Admin . 510.map showing areas affected by hurricanes in the caribbean area in summer and autumn the atlantic hurricane season runs from june 1st to november 30th the atlantic basin includes the atlantic ocean caribbean sea and gulf of mexico exemple 409 July until november.

Question 157-40 : Which statement about hurricanes in the north atlantic is correct ?

Their eye can be well observed by weather satellites

exemple 413 Their eye can be well observed by weather satellites


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