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Certification > weather : You are flying from east to west in the northern hemisphere at the 500 hpa ?

Question 143-1 : If the wind is from the north you are gaining altitude if the wind is from the south you are gaining altitude if you have a head wind you are gaining altitude if you have a tail wind you are losing altitude

.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

Divergence in the upper air results near the surface in ?

Question 143-2 : Falling pressure and likely formation of clouds rising pressure and likely dissipation of clouds falling pressure and likely dissipation of clouds rising pressure and likely formation of clouds

. 563.divergence in the upper air means convergence on the ground this a low pressure area and clouds may appears above it exemple 247 falling pressure and likely formation of clouds.falling pressure and likely formation of clouds.

In a low pressure system the convergence at the surface is caused by ?

Question 143-3 : Frictional forces centripetal forces the inbalance of the horizontal gradient force and the coriolis force the curvature of the isobars

. 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 251 frictional forces.frictional forces.

If the pressure surfaces bulge upwards in all levels then the pressure system ?

Question 143-4 : Warm high cold low cold high warm low

.if isobars bulge up in all level you have a high pressure at the surface and high temperatures in the air exemple 255 warm high.warm high.

A cold air pool ?

Question 143-5 : 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 develops usually in winter when very unstable maritime polar or maritime arctic air currents stream southwards along the eastern side of an extensive ridge of high pressure in association with occluded systems normally disappears at night and occurs almost exclusively in summer occurs frequently in winter to the south of the alps when this region is under the influence of cold north westerly airstream

exemple 259 is usually most evident in the circulation and temperature fields of the middle troposphere and may show little or no sign on a surface chartis usually most evident in the circulation and temperature fields of the middle troposphere and may show little or no sign on a surface chart

The stable layer at some height in the low troposphere of an older high ?

Question 143-6 : Subsidence inversion friction inversion radiation inversion trade wind inversion

.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 263 subsidence inversion.subsidence inversion.

A blocking anticyclone in the northern hemisphere is ?

Question 143-7 : A warm anticyclone quasi stationary situated between 50°n and 70°n quasi stationary situated between 50°n and 70°n a cold anticyclone situated between 50°n and 70°n a cold anticyclone steering depressions a cold anticyclone steering depressions situated over scandinavia

.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 267 a warm anticyclone, quasi stationary, situated between 50°n and 70°n.a warm anticyclone, quasi stationary, situated between 50°n and 70°n.

Which statement is true for hurricanes in the north atlantic ?

Question 143-8 : From the earth's surface up to the tropopause the core is warmer than its surroundings they intensify rapidly after landfall the diameter is 50 500 m their greatest frequency of occurrence is in winter

exemple 271 from the earth's surface up to the tropopause the core is warmer than its surroundings.from the earth's surface up to the tropopause the core is warmer than its surroundings.

Assume that an aircraft is flying in the northern hemisphere at the 500 hpa ?

Question 143-9 : If in this pressure surface the wind comes from the direction 360 degrees then true altitude is increasing if in this pressure surface the wind comes from the direction 180 degrees then true altitude is increasing if in this pressure surface the wind comes from the direction 270 degrees then true altitude is increasing if in this pressure surface the wind comes from the direction 090 degrees then true altitude is increasing

.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 275 if in this pressure surface the wind comes from the direction 360 degrees, then true altitude is increasing.if in this pressure surface the wind comes from the direction 360 degrees, then true altitude is increasing.

An aircraft is flying at fl 180 in the northern hemisphere with a crosswind ?

Question 143-10 : It decreases it increases it remains constant without knowing temperatures at fl 180 this question can not be answered

.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 279 it decreases.it decreases.

Which of the following is true concerning an aircraft that is flying at fl180 ?

Question 143-11 : There is no cross wind there is a cross wind from the left there is a cross wind from the right without knowing temperature at fl 180 this question can not be answered

.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 283 there is no cross wind.there is no cross wind.

The reason for the fact that the atmospheric pressure of a polar front ?

Question 143-12 : The temperature contrasts between arctic and equatorial areas are much greater in winter the low pressure activity of the sea east of canada is higher in winter the strong winds of the north atlantic in winter are favourable for the development of lows converging air currents are of greater intensity in winter

.the warm air is fairly consistent throughout the year but the cold air is much colder in the winter exemple 287 the temperature contrasts between arctic and equatorial areas are much greater in winter.the temperature contrasts between arctic and equatorial areas are much greater in winter.

In which of the following areas do surface high pressure systems usually ?

Question 143-13 : Azores se usa sw europe greenland azores ne canada iceland sw usa azores greenland sw europe ne canada

.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 291 azores, se usa, sw europe.azores, se usa, sw europe.

In the northern hemisphere with an anticyclonic pressure system the geostrophic ?

Question 143-14 : 340°/20 kt 030°/20 kt 340°/28 kt 030°/28 kt

.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 295 340°/20 kt.340°/20 kt.

Select the answer which you consider will complete correctly the following ?

Question 143-15 : Iceland / greenland usa siberia azores

.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 299 iceland / greenland.iceland / greenland.

The pressure system at position 'd' is . 319 ?

Question 143-16 : A col a secondary low a trough of low pressure a ridge of high pressure

.a col is an area of almost uniform pressure between two highs and two lows no isobars define its boundary . 586 exemple 303 a col.a col.

Considering the north atlantic region between 30°n and 65°n and the adjacent ?

Question 143-17 : Azores high and weak low over ne canada scandinavian high and azores high weak low over ne canada and scandinavian high azores low and icelandic high

.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 307 azores high and weak low over ne canada.azores high and weak low over ne canada.

Considering the north atlantic region between 30°n and 65°n together with the ?

Question 143-18 : Azores siberia siberia iceland canaries ne canada iceland greenland iberian peninsula

.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 311 azores, siberia.azores, siberia.

The arrows labelled 'r' represent the mean tracks of tropical revolving storms ?

Question 143-19 : December to april and are called cyclones december to april and are called tornadoes june to october and are called typhoons june to october and are called hurricanes

exemple 315 december to april and are called cyclonesdecember to april and are called cyclones

Which is true of a secondary depression in the northern hemisphere ?

Question 143-20 : It tends to move round the primary in a cyclonic sense it tends to move round the primary in an anticyclonic sense it rapidly closes on and merges with the primary it tends to maintain its position relative to the primary

.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 319 it tends to move round the primary in a cyclonic sense.it tends to move round the primary in a cyclonic sense.

The arrows labelled 's' represent the mean tracks of tropical revolving storms ?

Question 143-21 : May to november and are called cyclones december to april and are called cyclones may to november and are called hurricanes december to april and are called typhoons

. 588 exemple 323 may to november and are called cyclones.may to november and are called cyclones.

The arrows labelled 't' represents the mean track of tropical revolving storms ?

Question 143-22 : June to october and are called cyclones december to april and are called hurricanes june to october and are called tornadoes june to october and are called hurricanes

. 588 exemple 327 june to october and are called cyclones.june to october and are called cyclones.

The arrows labelled 'u' represent the tracks of tropical revolving storms which ?

Question 143-23 : July to october and are called typhoons january to march and are called willy willies may to july and are called cyclones december to april and are called tornadoes

. 588 exemple 331 july to october and are called typhoons.july to october and are called typhoons.

When if at all is a tropical revolving storm most likely to affect darwin on ?

Question 143-24 : December to april may to july august to october not experienced at darwin

.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 335 december to april.december to april.

A trough of low pressure on a surface synoptic chart is an area of ?

Question 143-25 : Convergence and widespread ascent divergence and subsidence divergence and widespread ascent convergence and subsidence

.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 339 convergence and widespread ascent.convergence and widespread ascent.

Which is true of a typical non frontal thermal depression ?

Question 143-26 : It forms over land in summer it forms over the ocean in summer it forms over the ocean in winter it forms over land in winter

.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 343 it forms over land in summer.it forms over land in summer.

During summer an anticyclone covers the british isles giving mainly clear skies ?

Question 143-27 : Become southerly to southwesterly and increase in velocity by afternoon back to nw and strengthen by mid afternoon increase from the north by mid morning becoming calm towards evening veer to easterly before becoming calm by the afternoon

.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 347 become southerly to southwesterly and increase in velocity by afternoon.become southerly to southwesterly and increase in velocity by afternoon.

During summer a weak pressure gradient covers a coastal airfield in eastern ?

Question 143-28 : Easterly to southeasterly and increase in velocitiy by afternoon easterly and then westerly by afternoon westerly and increase in velocity by afternoon westerly and then southerly by evening

.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 351 easterly to southeasterly and increase in velocitiy by afternoon.easterly to southeasterly and increase in velocitiy by afternoon.

For the same horizontal distance between adjacent isobars the gradient wind ?

Question 143-29 : 50°n with a cyclonic circulation 50°n in an anticyclone 30°n with a cyclonic circulation 30°n in an anticyclone

.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 355 50°n with a cyclonic circulation.50°n with a cyclonic circulation.

Over which areas can tropical cyclones occur ?

Question 143-30 : Caribbean sea gulf of bengal indian ocean east of madagascar india arabic sea atlantic ocean at 2°s australia gulf of bengal atlantic ocean at 20°s caribbean sea indian ocean at 20°s pacific ocean at 2°n

.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 359 caribbean sea, gulf of bengal, indian ocean east of madagascar.caribbean sea, gulf of bengal, indian ocean east of madagascar.

The hurricane season in the caribbean is mainly from ?

Question 143-31 : July until november october until january january until april april until july

. 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 363 july until november.july until november.

Which statement about hurricanes in the north atlantic is correct ?

Question 143-32 : Their eye can be well observed by weather satellites they intensify after landfall they move towards the equator they move with a speed of at least 60 kt

exemple 367 their eye can be well observed by weather satellitestheir eye can be well observed by weather satellites

You are flying at fl 340 250 hpa on the northern hemisphere .the wind is ?

Question 143-33 : Increase decrease decrease only if the pressure at the surface is decreasing on your route increase only if the temperature at your flight level is rising on your route

.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.with a cross wind from the right there must be low pressure behind and high pressure ahead you true altitude will increase air mass is warmer exemple 371 increase.increase.

You are flying in the northern hemisphere at 2000 ft over a flat country area ?

Question 143-34 : From your right from your left from ahead from behind

.if you stand with your back to the wind in the northern hemisphere low pressure is on your left high pressure is on your right buys ballot's law . 608.if you face the high pressure the wind affecting you will be from your right exemple 375 from your right.from your right.

Why do tropical revolving storms tend to develop mostly in the western parts of ?

Question 143-35 : Because there is a maximum of humidity as a result of the trade winds long sea passage because they are areas in which there is a strong progressive wind shear with increase of height because there is a maximal temperature difference between land mass and sea because the gulf formation of the coastlines triggers a strong rotary circulation

exemple 379 because there is a maximum of humidity as a result of the trade winds long sea passagebecause there is a maximum of humidity as a result of the trade winds long sea passage

Over the indian ocean and the bay of bengal tropical cyclones are ?

Question 143-36 : Occasionally observed in the average 12 per year rare in the average one every two years never observed frequently observed in the average 15 per year over the indian ocean but never over the bay of bengal

exemple 383 occasionally observed, in the average 12 per year.occasionally observed, in the average 12 per year.

Tropical revolving storms are not formed in ?

Question 143-37 : South atlantic ocean gulf of bengal waters around the philippines south indian ocean

exemple 387 south atlantic ocean.south atlantic ocean.

Between which latitudes are you most likely to find the region of travelling ?

Question 143-38 : 45° 70° 25° 45° 15° 25° 10° 15°

. 584 exemple 391 45° - 70°.45° - 70°.

A stationary observer in the northern hemisphere is situated in front of a ?

Question 143-39 : Backs veers initially veers then backs initially backs then veers

. 627.if the centre of the depression passes to the south of your position in the northern hemisphere the wind will change from south to nord passing by east a backing wind is a wind that turns counter clockwise exemple 395 backs.backs.

The region of the globe where the greatest number of tropical revolving storms ?

Question 143-40 : The north west pacific affecting japan taiwan korea and the chinese coastline the caribbean sea affecting the west indies mexico and the south east coastline of the usa the south western indian ocean affecting madagascar mauritius and the island of reunion the northern indian ocean affecting india sri lanka and bangladesh

. 588.the season for typhoons tropical revolving storms in north western pacific ocean extends from summer to autumn exemple 399 the north-west pacific, affecting japan, taiwan, korea and the chinese coastline.the north-west pacific, affecting japan, taiwan, korea and the chinese coastline.

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