Which of the following sets of conditions are most favourable to the ? [ Revision flight ]

Question 138-1 : Environmental lapse rate greater than saturated adiabatic lapse rate through a great vertical extent high relative humidity and an initial lifting process extensive isothermal layer ice particles and water droplets must exist just below the freezing level and orographic lifting environmental lapse rate less than saturated adiabatic lapse rate with dew point below 0°c and considerable surface heating environmental lapse rate less than dry adiabatic lapse rate with freezing level below the cloud base high relative humidity and strong surface winds

exemple 238 Environmental lapse rate greater than saturated adiabatic lapse rate through a great vertical extent, high relative humidity and an initial lifting process — Environmental lapse rate greater than saturated adiabatic lapse rate through a great vertical extent, high relative humidity and an initial lifting process

Which of the following statements is correct ?

Question 138-2 : The bergeron findeisen process is mainly based on the difference of maximum vapour pressure over water and over ice of the same temperature the principle of the bergeron findeisen process is mainly based on the difference in size of the cloud elements at mid latitudes the coalescense process is usually the initial process in the formation of precipitation in the tropics stratiform precipitation does not occur

Admin .the saturation vapour pressure is higher over water than over ice what that means that you will reach the frost point before you reach the dew point bergeron showed that in the mid latiudes because it is cold inside clouds precipitation is caused mainly by the coalence of water vapour onto ice crystals it does not explain everything and is just one of the theories of precipitation if there are no nuclei present you can raise the relative humidity to 460% before a drop will form spontaneously super saturation

Which of the following statements is true of the dew point of an air mass ?

Question 138-3 : It can only be equal to or lower than the temperature of the air mass it can be higher than the temperature of the air mass it can be used together with the air pressure to estimate the air mass's relative humidity it can be used to estimate the air mass's relative humidity even if the air temperature is unknown

exemple 246 It can only be equal to, or lower, than the temperature of the air mass. — Admin .the dewpoint temperature is the temperature at which the air can no longer hold all of its water vapor and some of the water vapor must condense into liquid water the dew point is always lower than or equal to the air temperature .if the air temperature cools to the dew point or if the dew point rises to equal the air temperature then dew fog or clouds begin to form .at this point where the dew point temperature equals the air temperature the relative humidity is 100% It can only be equal to, or lower, than the temperature of the air mass.

Which one of the following can provide the initial lifting leading to air mass ?

Question 138-4 : Advection of cold air over a warm sea mountain waves advection of warm air over a cold sea low level wind shear

exemple 250 Advection of cold air over a warm sea. — Admin .cold air over a warm surface gives convective lifting Advection of cold air over a warm sea.

Which of the following quantities remains unchanged if unsaturated air is ?

Question 138-5 : Mixing ratio difference between temperature and dewpoint temperature maximum vapour pressure maximum mixing ratio

exemple 254 Mixing ratio. — Admin .if unsaturated air dry adiabatic lapse rate is lifted until it reaches the lifting condensation level the ratio of water vapour to air by mass called 'mass ratio' or 'mixing ratio' will remained unchanged .the mixing ratio of water vapor in air is used to describe humidity Mixing ratio.

Which of the following processes will increase the stability of an air mass ?

Question 138-6 : Cooling by the underlying surface addition of water vapour in the lower layer warming of the air mass from below advection of colder air aloft

exemple 258 Cooling by the underlying surface. — Cooling by the underlying surface.

Which statement is correct for an absolutely unstable atmosphere ?

Question 138-7 : Visibility is good between showers the environmental lapse rate is less than 1°c / 100 m clouds are mainly of the stratiform type the dry adiabatic lapse rate is more than 1°c / 100 m

exemple 262 Visibility is good between showers. — Admin .if the environmental lapse rate elr is more than 3°c/1000 ft dry adiabatic lapse rate the environment is unstable .stable air will produce stratiform cloud .unstable air mass produces showers under cumulonimbus clouds outside showers visibilty is good Visibility is good between showers.

Relative humidity ?

Question 138-8 : Increases if the air is cooled whilst maintaining the vapour pressure constant is higher in warm air than in cool air is higher in cool air than in warm air decreases if the air is cooled whilst maintaining the vapour pressure constant

exemple 266 Increases if the air is cooled whilst maintaining the vapour pressure constant. — Admin .the air contracts therefore takes less volume .the water quantity does not change maintaining the vapour pressure constant' thus relative humidity increases Increases if the air is cooled whilst maintaining the vapour pressure constant.

What is true for the water vapour distribution in the layer between the surface ?

Question 138-9 : The lower part is relatively moist and the upper part is relatively dry the whole layer is relatively dry the whole layer is relatively moist the lower part is relatively dry and the upper part is relatively moist

exemple 270 The lower part is relatively moist and the upper part is relatively dry. — Admin .500 hpa = fl 180.se trade winds and ne trade winds converge at the itcz intertropical convergence zone they occur only in the lower part of the troposphere and are more pronounced over the oceans in the trade winds there is a maximum of humidity as a result of the trade winds long sea passage .in the upper part the air originates from the sub tropical high pressure belt is sinking warming adiabatically if temperature increases relative humidity will decrease the upper part is relatively dry The lower part is relatively moist and the upper part is relatively dry.

What is the dry adiabatic lapse rate ?

Question 138-10 : 3 0°c/1000 ft 2 0°c/1000 ft 1 5°c/1000 ft 3 5°c/1000 ft

exemple 274 3.0°c/1000 ft — Admin .the dry adiabatic lapse rate has a constant fixed value of 1°c/100 m 3°c/1000 ft 3.0°c/1000 ft

What is a characteristic of stable air ?

Question 138-11 : Stratiform clouds unlimited visibility fair weather cumulus clouds temperature decreases rapidly

exemple 278 Stratiform clouds. — Stratiform clouds.

What is a characteristic phenomenon for a stable atmosphere ?

Question 138-12 : Stratified clouds weak wind no precipitation many vertical currents

exemple 282 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 Stratified clouds.

In an unsaturated layer in the friction layer the air is well mixed by ?

Question 138-13 : Correspond to the dry adiabatic lapse rate at first coincide with the average dry adiabat and then coincide with the average wet adiabat always change toward a more stable position coincide with the average wet adiabat in the layer

exemple 286 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 Correspond to the dry adiabatic lapse rate.

Good visibility in the lower levels may be expected when ?

Question 138-14 : Cool dry air is moving over a warmer surface warm air is moving over a cold surface the atmospheric pressure is low the air temperature is low

exemple 290 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 Cool dry air is moving over a warmer surface.

A layer of stratus is most likely to be dispersed by ?

Question 138-15 : Insolation resulting in the lifting of the condensation level absorption of longwaved solar radiation in the stratus layer the release of latent heat due to precipitation adiabatic cooling due to subsidence

exemple 294 Insolation resulting in the lifting of the condensation level. — Insolation resulting in the lifting of the condensation level.

After a clear night cumuliform clouds are formed in the morning why can the ?

Question 138-16 : Because the surface temperature increases the wind speed is increasing because the cold air mass changes into a warm air mass because the stability increases because the difference between the temperature and the dewpoint temperature at the initial condensation level becomes smaller

exemple 298 Because the surface temperature increases. — Because the surface temperature increases.

Air masses which are being cooled from below are often characterized by ?

Question 138-17 : Fog poor visibility and layered clouds strong winds cumulus clouds good visibility uniform temperature good visibility continuous rain and freezing temperatures

exemple 302 Fog, poor visibility and layered clouds. — Fog, poor visibility and layered clouds.

An inversion is ?

Question 138-18 : An absolutely stable layer a conditionally unstable layer an unstable layer a layer that can be either stable or unstable

exemple 306 An absolutely stable layer — An absolutely stable layer

An unstable air mass is forced to ascend a mountain slope what type of clouds ?

Question 138-19 : Clouds with considerable vertical development and associated turbulence stratiform clouds with considerable turbulence layer like clouds with little vertical development stratiform clouds with a temperature inversion

exemple 310 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 Clouds with considerable vertical development and associated turbulence.

8/8 stratus base 200 ft/agl is observed at sunrise at an aerodrome in the north ?

Question 138-20 : Winter ovc base 500 ft/agl summer sct base 3000 ft/agl winter clear sky summer bkn cb base 1500 ft/agl winter bkn base 2500 ft/agl summer bkn base 3500 ft/agl winter sct base 3000 ft/agl summer ovc base 500 ft/agl

exemple 314 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 Winter: ovc, base 500 ft/agl, summer: sct, base 3000 ft/agl.

The dewpoint temperature ?

Question 138-21 : Can be reached by cooling the air whilst keeping pressure constant can be reached by lowering the pressure whilst keeping temperature constant can not be equal to the air temperature can not be lower than the air temperature

exemple 318 Can be reached by cooling the air whilst keeping pressure constant — Can be reached by cooling the air whilst keeping pressure constant

The amount of water vapour which air can hold largely depends on ?

Question 138-22 : Air temperature stability of air relative humidity the dew point

exemple 322 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 Air temperature.

A given mass of air is saturated with water vapour no condensed water .if ?

Question 138-23 : The amount of water vapour remains constant the amount of water vapour decreases relative humidity increases relative humidity remains constant

exemple 326 The amount of water vapour remains constant. — Revised ecqb03 july 2016 The amount of water vapour remains constant.

Which of the following changes of state is known as freezing ?

Question 138-24 : Liquid to solid gas to solid liquid to gas solid to liquid

exemple 330 Liquid to solid. — Cqb15 july 2011 Liquid to solid.

Consider a parcel of air which is moved upwards in the surrounding air by an ?

Question 138-25 : Tends to gain altitude after being released tends to maintain its new altitude after being released tends to return to its original altitude when it is released tends to descend when it is released it will move to and maintain an altitude below its original altitude

exemple 334 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 Tends to gain altitude after being released.

In which of the following changes of state is latent heat absorbed ?

Question 138-26 : Liquid to gas liquid to solid gas to solid gas to liquid

exemple 338 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 Liquid to gas.

In which of the following changes of state is latent heat released ?

Question 138-27 : Gas to solid solid to liquid solid to gas liquid to gas

exemple 342 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 Gas to solid.

What is foehn wind ?

Question 138-28 : 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 it is a flow of warm air up a slope of a hill caused by surface heating it is a warm and moist anabatic wind that usually carries precipitation it is an adiabatically heated wind blowing down a mountain side the temperature on the lee side is normally lower than on the windward side of the mountain at the same level

exemple 346 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. — 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.

What is 'mixing ratio' ?

Question 138-29 : The number of grammes of water vapour per kilogramme of dry air the percentage of water drops per volume unit of dry air the volume of water vapour which is mixed with each volume unit of dry air the ratio between actual water vapour content and saturated water vapour content

exemple 350 The number of grammes of water vapour per kilogramme of dry air. — The number of grammes of water vapour per kilogramme of dry air.

A night in january has been cold and clear in the forenoon of the next day an ?

Question 138-30 : The aircraft suffers reduced lift and thrust due to a temperature inversion at the top of the fog the additional weight gained by water which has been gathered on wings and fuselage during flight through the fog reduces the lift the water which has been gathered during flight through the fog modifies the aerodynamic properties of the aircraft thus reducing lift the aircraft is under influence of a mountain breeze descending air from the surrounding hills due to the incident sunshine

exemple 354 The aircraft suffers reduced lift and thrust due to a temperature inversion at the top of the fog. — The aircraft suffers reduced lift and thrust due to a temperature inversion at the top of the fog.

Which of the following changes of state is known as melting ?

Question 138-31 : Solid to liquid solid to gas liquid to solid liquid to gas

exemple 358 Solid to liquid. — Solid to liquid.

In which of the following changes of state is latent heat absorbed ?

Question 138-32 : Solid to liquid liquid to solid gas to solid gas to liquid

exemple 362 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 Solid to liquid.

Which of the following changes of state is known as evaporation ?

Question 138-33 : Liquid to gas liquid to solid gas to solid solid to liquid

exemple 366 Liquid to gas. — Ecqb01 2013 Liquid to gas.

Which of the following changes of state is known as condensation ?

Question 138-34 : Gas to liquid gas to solid liquid to gas liquid to solid

exemple 370 Gas to liquid. — Ecqb01 2013 Gas to liquid.

Check the correctness of the following statements .1 the maximum water vapor ?

Question 138-35 : 1 is incorrect and 2 is correct 1 and 2 are incorrect 1 is correct and 2 is incorrect 1 and 2 are correct

exemple 374 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 1 is incorrect and 2 is correct.

In an isothermal layer the state of the atmosphere is ?

Question 138-36 : Absolutely stable absolutely unstable neutral conditionally unstable

exemple 378 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 Absolutely stable.

In which of the following changes of state is latent heat absorbed ?

Question 138-37 : Solid to gas liquid to solid gas to solid gas to liquid

exemple 382 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 Solid to gas.

Given the following information what is the approximate relative humidity of ?

Question 138-38 : 75% 50% 55% 95%

exemple 386 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% 75%.

As regards water which state change process delivers the main part of the ?

Question 138-39 : Condensation freezing evaporation sublimation

exemple 390 Condensation. — Ecqb03 july 2016 Condensation.

Several physical processes contribute to atmospheric warming which of the ?

Question 138-40 : Convection and condensation solar radiation and conduction absorption and vaporisation absorption and evaporation

exemple 394 Convection and condensation. — Convection and condensation.

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