航空气象学课后习题电子档

1、Thunderstorm hazards:are only encountered in the cloudare unl kely under the base of the cloudH may be encountered some miles from the cloud 口 are unl kely near the top of the cloudA microburst associated with a Cb cloud will normally occur:from a point mid-way up in the cloud 一 near the base of the

2、 cloud 口 only ahead of the surface impact pointanywhere up to 10 miles ahead of the cloudThe cumulus stage of a TS is characterised by:the beginning of precipitation 0 updraughts onlystronger downdraughts than updraughtsthe anvilThe mature stage of a TS is characterised by:口 the anvil 口 updraughts o

3、nlythe beginning of precipitation 口 stronger downdraughts than updraughtsVertical windshear is the change of(1) wind vector with height, and horizontal windshear is the change of(2) wind vector with distance.口 1. vertical 2. horizontal 1. honzontal 2. horizontal 口 1. honzontal 2. vertical 口 1. verti

4、cal 2 verticalWhen the aircraft encounters turbulence it can experience fluctuations in its indicated airspeed. Fluctuations of between 15 and 26 knots would ndicate:口 light turbulence 口 bad turbulence 口 moderate turbulence 口 severe turbulenceWhich of the following situations will give the most seve

5、re airframe icing?stratiform clouds in the tropics 口 cumuliform clouds in temperate regions 口 stratiform clouds in temperate regionsQ cumuliform clouds in the tropicsRain ice most commonly occurs:behind a cold front below the freezing level口 behind a warm front below the freezing levelahead of a col

6、d front above the freezing level ahead of a warm front above the freezing levelThe ITCz will normally reach its most northerly point of travel in:口 June July September 口 AugustThe sub-tropical highs are due to an accumulation of air at the latitudeThe monsoon low of Asia is an important example ofH

7、a thermal low which forms in summerall of the alternatives are correctan orographic low which forms in winter 口 a tropical depression which forms in summerAcold low:deepens at a忻tude and turns into a high pressure 口 weakens at altitude and turns into a high pressureQ deepens at altitude and is more

8、intense than a warm lowweakens at altitude and is less intense that a warm lowA warm occlusion occurs when theQ air ahead of the warm front is colder than the air behind the cold frontair behind the cold front is colder than the air ahead of the warm frontwarm front is catching up the cold front 口 a

9、ir ahead of the warm front is warmer than in the warm sectorThe speed of movement for a cold occlusion is: about the same as for the cold frontfaster in the winter than in the summerhalf of the geostrophic wind speed 口 about the same as for the warm frontThe average gradient of the slope of a cold f

10、ront is:The average gradient of the slope of a warm front is:Virga is:precipitation from the anvil of a Cb behind a cold front precipitation that doesnl reach the groundthe first precipitation to reach the ground ahead of the warm front 口 precipitation from St ahead of the warm frontFor an a rcraft

11、flying directly towards a warm front from the cold side, the succession of cloud types to be expected as the front is approaches is:口 Ci-Cc-Ac-Ns Ac-Cu-Sc-St Ci-Cs-As-Ns 口 Ci-Cs-As-AcWhat factors associated wrth the passage of a front would indicate an increased risk of windshear?Front speed 20 knot

12、s or more, small change in wind direction, temperature change X- 10旗Front speed 20 knots or more, sharp isobar angle, temperature difference across thefront 10旗Front speed 30 knots or more, temperature change +/-10其 shallow isobar angleFront speed 30 knots or more, temperature difference across the

13、front of 5策 or more, sharp isobar angleIf air transit is heated from below it ends to become more口 stable 口 none of the alternatives are correct 口 neutrally stable unstableAn air mass is a large volume of air with similar characteristics of:pressure and stabilitypressure tendency and dew pointQ temp

14、erature and humidity 口 relative humidity and pressureLeast reduction in visibility is caused by: sleet rainhail 口 snowPrecipitation from Sc is most likely to be:口 heavy continuousheavy showerslight showerslight intermittentRain/hail showers are described as moderate when the amount of precipitation

15、is:口 2 to 10 mm per hour 口 4 to 50 mm per hour0.5 to 4 mm per hour2 to 10 cm per hourPrecipitation falling from Ns is most likely to be:moderate drizzleheavy hail showersmodercte continuous ramlight snow showersWhich of the following could be the precipitation falling from Cu?口 Moderate continuous s

16、now 口 Snow showers Heavy continuous rain Moderate continuous rainFrom which cloud is hail most like to fall? Ns Ci Gu 口 CbDrizzle is most likely to fall from:口 alto stratus 口 cumulus 口 status 口 nimbostratusGreatest reduction in visibility is caused by:Frontal fog. is very low frontal stratus 口 often

17、 fcrms at cold fronts rather than warn fronts forms when frontal ram cools down the air ahead of the front 口 is advection fog in the warm sectorSteaming fog occurs in the winter when very cold air picks up moisture from, and is heated by relatively warm water winter over land when warm and moist air

18、 moves in over the cold surface口 arctic regions during the summer when warm air from the south moves in over the cold sea口 tropical regions during the day when wet ground is heated by the sunWhen surface visibility is reduced to 1200 m due to water droplets in suspension, the weather is referred to

19、as:口 fog 口 smoke fog haze 口 mistWhen surface visibility is reduced to 5000 m by dust particles in suspension, the weather is termed: haze 口 smoke fog 口 fog mistFog is defined as visibility reduced to口 1000 m or less due to water vapour in the atmosphere below 1000 m due to water droplets in the atmo

20、sphere 1000 m to 2000 m due to water droplets in the atmosphere 口 1000 m or above due to water droplets in the atmosphereCirriform clouds are mainly composed of:water croplets 口 a mixture of water droplets and ice particlessupercooled water dropletsQ ice particlesThe two main families of clouds are:

21、cirriform and cumuliformaltoform and stratoform 口 nimbus and layered stratiform and cumuliformAltocumulus lenticularis is associated with:instability through a thick layerQ mountain waves 口 an area of turbulence immediately behind a mountain rangea surface inversionThe halo phenomenon is normally ca

22、used by a:口 thin layer of stratus layer of cirrostratuslayer of cirrus before a cold frontthin layer of cumulusWhich of the following processes within a layer of air may lead to the building of cumuliform clouds，Q Convection 口 Subsidence Frontal lifting within stable layers 口 RadiationA cap clcud wi

23、ll form:above a turbulence layeraround the top of a cumuliform cloudbecause of orographic uplift 口 in a layer with instabilityAdiabatic cooling is said to occur when a parcel of air口 descends and becomes cooler and denserQ ascends and expands, without exchanging heat energy 口 descends and loses heat

24、 to the surrounding environment ascends and loses heat to the surrounding environmentAn ELR which is absolutely unstable is:口 3篌 per 1000 ft口 2及 per 1000 ft 口 1 per 1000 ft 4澳 per 1000 ftAn ELR which is absolutely stable is:| per 1000 ft 口 4 策 per 1000 ft2 旗 per 1000 ft3 班 per 1000 ftAn ELR which is

25、 conditionally unstable is:4篌 per 1000 ft0.5旗 per 1000 ft 口 2 per 1000 ft1 滨 per 1000 ftThe SALR in tropical areas is less than that in temperate regions because:a large amount of latent heat is released during condensation which reduces the rate of cooling a large amount of latent heat is absorbed

26、during condensation which reduces the rate of coolingthe sattration content in the tropics is lowera small amount of latent heat is released during condensation which increases the rate of coolingWhen a parcel of air ascends it will:release latent heat when becoming saturated口 be cooled by the value

27、 of the environmental lapse ratecool faster if it becomes saturatedexpand and become less humid since the surrounding air is cold and dryBoth dry and saturated air will be unstable when ELRvSALR SALRDALR 口 ELRSALR ELRDALRWhich of the following formulae is correct for finding the Relative Humidity (R

28、H)，口 RH 二 Vapour pressure x 1/Saturation vapour pressure x 100% RH = Absolute humidity x 100%/Actual humidity 口 RH = Saturation content x 100%/Absolute humidityRH = Amount of water vapour present in the air x 100%/ Maximum amount of water vapour the air can holdAir that does not contain the maximum

29、amount of water vapour is:日 unsaturated 口 foggy 口 moist saturatedClear air turbulence associated wrth the polar front jet stream will be found:below the tropopause on the warm side of the jet 口 above the tropopause on the warm side of the jet below the tropopause on the cold side of the jetabove the

30、 tropopause on the cold side of the jetThe wind at 10 000 ft is 045?15 kt. If the thermal wind in the layer 4000 ft to 10 000 ft is 20 kt, with cold air to the North, the 4000 ft wind is (assume northern hemisphere): 070232 kt250732 kt320716 kt140714 ktThe thermal wind speed in the layer from 2000 f

31、t to 7000 ft is 20 kt with low temperature to the Ncrth-West. k the 2000 ft W/V is 210720 kt, the wind at 7000 ft is (assume northern hemisphere): 215940 kt31021。kt040736 kt170736 ktA Foehn wind flows over a mountain top of 7000 ft. The temperature at the base on the windward side is 15旗.The cloud b

32、ase on the windward side is 3000 ft. The cloud base on the lee side is 6000 ft. What is the temperature at the base of the leeward side of the mountain?15馍 国19.5彼Severe windshear is likely to occur with the passage of a(1) and windshear that occurs with the passage of a(2) is likely to be less sever

33、e.口 L vigorous cold front 2 warm frontL vigorous cold front 2 cold front口 1. vigorous warm front 2. cold front1. vigorous warm front 2. warm frontLow level windshear may occur in association wrth which of the following:Warm frontsCold fronts口 Neither2 only1 onlyBothWhat factors associated with the p

34、assage of a front would indicate an increased risk of windshear? Fast moving front, temperature change +/-10彼? shallow isobar angleFast moving front temperature difference across the front of 5铁 or more, sharp isobar angle口 Slow moving front, small change in wind direction temperature change +/-10策

35、Slow moving front sharp isobar angle, temperature difference across the front +/-10篌The depth of the friction layer will be greatest by:口 day, over the seaH day over the land 口 night, ever the sea 口 night over the landlb calculate the surface wind at night over the sea, find the 2000 ft wind: back i

36、t by 10?in direction in the southern hemisphere and reduce the speed by 二 口 back it by 25?in direction in the northern hemisphere and reduce the speed by 二 口 back it by 30?in direction in the southern hemisphere and reduce the speed by 二 back it by 15?in direction in the northern hemisphere and redu

37、ce the speed by 二With an increase in height from the surface to the top of tne friction layer the wind is likely to: back and increase in the southern hemisphere 口 veer and decrease in the northern hemisphere 口 back and increase in the northern hemisphereveer and increase in the southern hemisphereI

38、n the southern hemisphere the 2000 ft wind velocity:veers and decreases from the surface wind velocity at middayveers and increases from the surface wind velocity at midday 口 backs and decreases from the surface wind velocity at middayD backs and increases from the surface wind velocity at middayThe

39、 magnitude of the Geostrophic Force:decreases with an increase in density 口 decreases with a decrease in wind speed 口 increases with a decrease in wind speeddecreases with an increases in latitudeRegarding the geostrophic wind at the equator, the geostrophic:force does not apply and winds follow pre

40、ssure gradients from high to lowforce does not apply and winds are unable to reach beyond light and variable strengthD equation breaks down and the wind follows directions which are not related to the isobarsD equation breaks down and a large pressure gradient is required for the wind to follow the

41、isobarsCoriolis force affects the flow of air from high pressure to low pressure by deflecting it to the:left in the northern hemisphere口 right in the southern hemisphere right in the northern hemisphere口 right in both hemispheresBuys Ballots law states that if you stand:D with your back to the wind

42、 then the high pressure is on your left in the northern hemispherewith your back to the wind then the low pressure is on your left in the northern hemispherefacing the wind then the high pressure is on your right in the northern hemispherewith your back to the wind then the low pressure is on your l

43、eft in both hemispheresThe wind that blows parallel to straight isobars at 2000 ft is called the:口 wind gradient geostrophic windgradiert windcyclostrophic componentWhen the surface wind changes in direction from South to south-westerly, what is the change of direction?口 It has backed in both hemisp

44、heres It has backed in the southern hemisphere and veered in the northern hemisphere 口 It has veered in the southern hemisphere and backed in the northern hemisphere 口 It has yeered in both hemispheresAn aircraft flies over an airfield. QNH 988 hPa3 at a pressure altitude of 4500 ft. If the elevatio

45、n of the airfield is 125 ft and a change in pressure of 1 hPa is equivalent to 29 ft.What is the true height of the aircraft? 3900 ft 3775 ft 2650 ft 4375 ftAn aircraft altimeter set at QNH for a specific airport, is expected to give correct indication of:the elevation of the airport, regardless of

46、temperature 口 0 ft regardless of temperature日 llit; de/aliwr i uf IIit; dir puil, bul unly in a，匕“dtud lenipcialureOft but only in a standard temperatureWhich of the following altimeter settings indicates the airport elevation when landing? If QNH of the airport is set as reference 口 If QFE of the a

47、irport is set as reference 口 If QFF of the airport is set as reference At standard settingThe difference between QNH and QFE at an airport:口 depends on the air pressure as well as the air temperature at the airport 口 depends on the (ambient) air temperature at the airport depends on the air pressure

48、 at the airport 口 is always the sameJLanding at an airport you have correctly set QNH 1023 hPa as the reference pressure on your altimeter. The altimeter indicates 1200 ft after landing. Suppose that you change the pressure reference to standard setting (1013 hPa). What will your altimeter indicate

49、(use 1 hPa = 30 ft)? Oft 1200 ft 900 ft 1500 ftFlying at FL40 you reset the altimeter to reference pressure 993 hPa The altimeter will indicate:口 3740 ft 3460 ft 4540ft 4340ftThe temperature at an airport, wrth an elevation of 500 ft. is JO演.For landing. QNH is set as the reference on the altimeter.

50、 What does it indicate on landing? 500 ft 450 ft Oft 口 550 ftSuppose you are flying with a constant attitude on the altimeter and your altimeter setting is unchanged Which two of the alternatives mentioned below interact to give minimum actual altitude?Flying from low air pressure to highFlying from

51、 high air pressure to lowFlying from warm air mass to a cold oneFlying from a cold air mass to a warm one口 2 and 4 2 and 3口 1 and 3口 1 and AYour pressure altimeter is set at 1000 hPa. You have been cleared to join the traffic circuit at 2600 ft and the current QNH is 1010 hPa You join the circuit at

52、 2600 ft but forget to reset your altimeter Other aircraft with the correct altimeter setting flying at an indicated 2600 ft in the circuit will, compared to you, be flying (1 hPa = 30 ft):口 100 ft below日 300 ft below 300 ft above口 100 ft aboveAn aircraft is at an indicated altitude of 7500 ft over

53、A (270 ftAMSL) with the correct QNH of 1030 hPa set on the altimeter The aircraft then flies to B (1060 ft AMSL). maintaining 7500 ft with 1030 hPa still set on the altimeter. If the QNH at B is 982 hPa and assuming 1 hPa = 30 ft. the aircrafts height above B is: 5000 ft7880 ft6060 ft5270 ftA pressu

54、re altimeter can indicate different altitudes depending on the setting. With regard to the setting it can generally be said that it indicates:altitude corresponding to the difference between the reference pressure and the pressure where the instrument is口 altitude in the standard atmosphere at +15策

55、口 altitude above mean sea level at +15滨height above terrainA barometric altimeter always indicates:standard altitude 口 altitude referred to the set altitude referencecorrect altitude to the terrain below 口 the dynamic pressureIf an aircraft, without changing altimeter reference, flies so that the al

56、timeter indicates the same altitude, this always means that the. air pressure around the aircraft is unchanged actual altitude above sea level is unchanged 口 dclual lieiyhl above Ihe intan gruund level 过 unchanged 口 air pressure at sea level is unchangedWhat is the average temperature lapse rate as

57、defined in the ISA? 2 旗 per 1000 ft1.5旗 per 1000 ft1 楚 per 1000 ft2 5馍 per 1000 ftThe actual temperature at 12 000 ft is -10然 This temperature expressed in terms of ISA is:口 ISA+14 浜ISA+1 淡 ISA-啜 口 ISA-14 策Which of the following statements is true with regard to pressure altitude density altitude an

58、d air temperature?Density altitude is unchanged with rising temperature at constant pressure altrtudeThere is no connection between the quantities Density cillilude incredes wilh rising Lemperaluie alpressure allilude口 Density altitude decreases with rising temperature at constant pressure altitudeW

59、hat is the density altitude when the pressure altitude is 10 000 ft at OAT -30筑，13 000 ft 口 7000 ft6400 ft13 600 ftRegarding density:humicity have no affectincreased humidity will lead to increased density increased humidity will lead to decreased density decreased humidity will lead to decreased de

60、nsityCompared to the equator, air density at the poles is:口 higher and decrease more slowly with height higher and decreases more quickly with height lower and decreases more quickly with height 口 lower and decreases more slowly with heightWhich one of the following conditions gives the shortest tak