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Question 148-1 : What is a characteristic phenomenon for a stable atmosphere ? [ Certification weather ]

Stratified clouds

Admin .the words to distinguish between clouds produced by instability and other clouds are stratiform/stratified for clouds forming in a stable layer and convective clouds for clouds developing in an unstable environment stratiform clouds are basically flat and layered . stable clouds include cirrostratus altostratus nimbostratus and stratus .convective clouds have vertical development and often extend through a significant depth of the troposphere .convective clouds include cumulonimbus cumulus cirrus and altocumulus exemple 248 Stratified clouds.

Question 148-2 : In an unsaturated layer in the friction layer the air is well mixed by turbulence the layer remains unsaturated after some time the vertical temperature profile will ?

Correspond to the dry adiabatic lapse rate

Admin .if the layer remains unsatured we have a conditional stability depending on dry or satured air but mixing the temperature in the turbulence layer will change the vertical temperature profile by increasing the vertical rate of temperature change it will correspond to the dry adiabatic lapse rate exemple 252 Correspond to the dry adiabatic lapse rate.

Question 148-3 : Good visibility in the lower levels may be expected when ?

Cool dry air is moving over a warmer surface

Admin .good visibility is associated with unstable air a cool dry air moving over a warm surface will become unstable exemple 256 Cool dry air is moving over a warmer surface.

Question 148-4 : A layer of stratus is most likely to be dispersed by ?

Insolation resulting in the lifting of the condensation level

exemple 260 Insolation resulting in the lifting of the condensation level.

Question 148-5 : After a clear night cumuliform clouds are formed in the morning why can the base of these clouds become higher during the day ?

Because the surface temperature increases

exemple 264 Because the surface temperature increases.

Question 148-6 : Air masses which are being cooled from below are often characterized by ?

Fog poor visibility and layered clouds

exemple 268 Fog, poor visibility and layered clouds.

Question 148-7 : An inversion is ?

An absolutely stable layer

exemple 272 An absolutely stable layer

Question 148-8 : An unstable air mass is forced to ascend a mountain slope what type of clouds can be expected ?

Clouds with considerable vertical development and associated turbulence

Admin .unstable air = cumulus.stable air = stratus .this question has been seen at the exam with this wording a conditionally unstable air mass is forced to ascend a mountain slope what type of clouds can be expected .right answer remains unchanged exemple 276 Clouds with considerable vertical development and associated turbulence.

Question 148-9 : 8/8 stratus base 200 ft/agl is observed at sunrise at an aerodrome in the north of france.the qnh is 1028 hpa and there is a variable wind of 3 kt .what change in these clouds is likely at 1200 utc in summer and winter ?

Winter ovc base 500 ft/agl summer sct base 3000 ft/agl

Admin .winter limited heating during the day will raise the cloud base slightly .summer more heating will raise the cloud base and dissipate some of the cloud .the relatively high pressure 1028 hpa and light winds indicate anticyclonic conditions with stable air exemple 280 Winter: ovc, base 500 ft/agl, summer: sct, base 3000 ft/agl.

Question 148-10 : The dewpoint temperature ?

Can be reached by cooling the air whilst keeping pressure constant

exemple 284 Can be reached by cooling the air whilst keeping pressure constant

Question 148-11 : The amount of water vapour which air can hold largely depends on ?

Air temperature

Admin .the most commonly used measure of humidity is relative humidity relative humidity can be simply defined as the amount of water in the air relative to the saturation amount the air can hold at a given temperature multiplied by 100 air with a relative humidity of 50% contains a half of the water vapor it could hold at a particular temperature . 501. concept of relative humidity .we can say that the amount of water vapour which air can hold largely depends on air temperature exemple 288 Air temperature.

Question 148-12 : A given mass of air is saturated with water vapour no condensed water .if temperature increases ?

The amount of water vapour remains constant

Revised ecqb03 july 2016 exemple 292 The amount of water vapour remains constant.

Question 148-13 : Which of the following changes of state is known as freezing ?

Liquid to solid

Cqb15 july 2011 exemple 296 Liquid to solid.

Question 148-14 : Consider a parcel of air which is moved upwards in the surrounding air by an external force .which one of the following situations describes instability the parcel ?

Tends to gain altitude after being released

Take parcels of air that are initially in equilibrium with their environment by equilibrium we mean that the temperature density of the air inside a stationary parcel is the same as its environment now give a parcel of air a push upward for a parcel in contact with the ground an upward push is the only choice possible but air parcels aloft may be given a push upward or downward to test their stability if after a push upwards the test parcel returns to its original position the layer of the atmosphere where the test took place is said to be stable .the atmosphere is unstable when if a parcel starting at equilibrium is displaced slightly upward relative to its surrounding environment it finds itself warmer than its environment at its new altitude and therefore continues to rise spontaneously away from its starting point exemple 300 Tends to gain altitude after being released.

Question 148-15 : In which of the following changes of state is latent heat absorbed ?

Liquid to gas

Easa 2014..latent heat is absorbed when going from liquid to gas solid to liquid solid to gas .latent heat is released when going from gas to liquid liquid to solid gas to solid exemple 304 Liquid to gas.

Question 148-16 : In which of the following changes of state is latent heat released ?

Gas to solid

Easa 2014..latent heat is absorbed when going from liquid to gas solid to liquid solid to gas .latent heat is released when going from gas to liquid liquid to solid gas to solid exemple 308 Gas to solid.

Question 148-17 : What is foehn wind ?

It is an adiabatically heated wind blowing down a mountain side the temperature on the lee side is normally higher than on the windward side of the mountain at the same level

exemple 312 It is an adiabatically heated wind blowing down a mountain side. the temperature on the lee side is normally higher than on the windward side of the mountain at the same level.

Question 148-18 : What is 'mixing ratio' ?

The number of grammes of water vapour per kilogramme of dry air

exemple 316 The number of grammes of water vapour per kilogramme of dry air.

Question 148-19 : A night in january has been cold and clear in the forenoon of the next day an airfield is in imc due to fog which extends to a height of 700 ft a heavily laden aircraft departs and when breaking through the top of the fog experiences temporary bumpiness and a sudden decrease in climb rate . ?

The aircraft suffers reduced lift and thrust due to a temperature inversion at the top of the fog

exemple 320 The aircraft suffers reduced lift and thrust due to a temperature inversion at the top of the fog.

Question 148-20 : Which of the following changes of state is known as melting ?

Solid to liquid

exemple 324 Solid to liquid.

Question 148-21 : In which of the following changes of state is latent heat absorbed ?

Solid to liquid

Easa 2014..latent heat is absorbed when going from liquid to gas solid to liquid solid to gas .latent heat is released when going from gas to liquid liquid to solid gas to solid exemple 328 Solid to liquid.

Question 148-22 : Which of the following changes of state is known as evaporation ?

Liquid to gas

Ecqb01 2013 exemple 332 Liquid to gas.

Question 148-23 : Which of the following changes of state is known as condensation ?

Gas to liquid

Ecqb01 2013 exemple 336 Gas to liquid.

Question 148-24 : Check the correctness of the following statements .1 the maximum water vapor pressure is higher over ice than over water with the same temperature .2 for unsaturated air the dew point temperature is lower than the outside temperature ?

1 is incorrect and 2 is correct

Admin .when the dew point is lower than oat the air is unsaturated .when the dew point is equal to oat the air is saturated exemple 340 1 is incorrect and 2 is correct.

Question 148-25 : In an isothermal layer the state of the atmosphere is ?

Absolutely stable

Easa 2014..an isothermal layer is a layer of air in which the temperature remains constant with height .for example the layer just above the tropopause is absolutely stable from 12 km to 25 km the temperature does not vary with height it is an isothermal layer where we have absolute stability exemple 344 Absolutely stable.

Question 148-26 : In which of the following changes of state is latent heat absorbed ?

Solid to gas

Easa 2014..latent heat is absorbed when going from liquid to gas solid to liquid solid to gas .latent heat is released when going from gas to liquid liquid to solid gas to solid exemple 348 Solid to gas.

Question 148-27 : Given the following information what is the approximate relative humidity of the air mass .temperature 15° c.dew point 10° c ?

75%

Admin .usually we need to know the 'water pressure of water' .since this data is not given we can use this basic formula .relative humidity = dew point / temperature x 100.relative humidity = 10 / 15 x 100 = 67% .closest answer is 75% exemple 352 75%.

Question 148-28 : As regards water which state change process delivers the main part of the energy in thunderstorms and hurricanes ?

Condensation

Ecqb03 july 2016 exemple 356 Condensation.

Question 148-29 : Several physical processes contribute to atmospheric warming which of the following contribute the most ?

Convection and condensation

exemple 360 Convection and condensation.

Question 148-30 : What is the mean temperature deviation from isa for the frankfurt roma route . 403 ?

4°c colder than isa

exemple 364 4°c colder than isa.

Question 148-31 : During a high altitude flight favourable contrail formation conditions are ?

High humidity low temperatures and presence of aerosols

exemple 368 High humidity, low temperatures and presence of aerosols.

Question 148-32 : An inversion is a layer of air in which the temperature ?

Increases with increasing altitude

exemple 372 Increases with increasing altitude.

Question 148-33 : In which of these cloud types can icing be virtually ruled out ?

Cirrus ci

Admin .cirrus clouds are very high clouds and they are composed of ice crystals .cirrus clouds do not result in structural icing the reason for that is the moisture is already frozen in the form of ice crystals and it doesn't deposit on the airframe as do super cooled water droplets which might exist in stratus or cumulus clouds . 642 exemple 376 Cirrus (ci).

Question 148-34 : The most likely reason for radiation fog to dissipate or become low stratus is ?

Increasing surface wind speed

exemple 380 Increasing surface wind speed.

Question 148-35 : What conditions are most likely to lead to the formation of hill fog ?

Humid stable air mass wind blowing towards the hills

exemple 384 Humid stable air mass, wind blowing towards the hills.

Question 148-36 : Clouds fog or dew will always be formed when ?

Water vapour condenses

Admin .a cloud is a large collection of very tiny droplets of water or ice crystals fog and dew are a collection of very tiny droplets of water .condensation is the process by which water vapor in the air is changed into liquid water exemple 388 Water vapour condenses.

Question 148-37 : Which of the following is a cause of stratus forming over flat land ?

Radiation during the night from the earth surface in moderate wind

exemple 392 Radiation during the night from the earth surface in moderate wind.

Question 148-38 : Which of the following processes within a layer of air may lead to the building of cu and cb clouds ?

Convection

exemple 396 Convection.

Question 148-39 : What are the characteristics of cumuliform clouds ?

Large water droplets instability turbulence showers and mainly clear ice

exemple 400 Large water droplets, instability, turbulence, showers and mainly clear ice.

Question 148-40 : Which of the following clouds are classified as medium level clouds in temperate regions ?

As ac

Admin . 503 exemple 404 As, ac.


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