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Question 159-1 : What wind direction will occur over the land at point e . 388 ? [ Learning aircraft ]
West.
.at low elevations, friction will slow the air, and hence the coriolis force will be less effective in its deflection of the wind.. 561.as the elevation decreases the direction backs changes direction in an counter clockwise motion in northern hemisphere..at mid latitude, over land, wind speed in friction layer decrease by 50%. angle between wind direction and isobars changes by 30° value to be used in examinations. we are in northern hemisphere from the way the fronts are positioned , therefore at point e, the wind is from the west.
Question 159-2 : What wind direction will occur over the land at point b . 389 ?
Southwest.
.at low elevations, friction will slow the air, and hence the coriolis force will be less effective in its deflection of the wind.. 561.as the elevation decreases the direction backs changes direction in an counter clockwise motion in northern hemisphere..at mid latitude, over land, wind speed in friction layer decrease by 50%. angle between wind direction and isobars changes by 30° value to be used in examinations. we are in northern hemisphere from the way the fronts are positioned , therefore at point b, the wind is from the southwest.
Question 159-3 : What kind of turbulence is caused by the friction of air flowing over the earth's surface ?
Mechanical turbulence.
Ecqb01 june 2013
Question 159-4 : Which of the following values corresponds to a ne wind ?
045°.
Question 159-5 : Which of the following values corresponds to a se wind ?
135°.
Question 159-6 : Which of the following values corresponds to a nw wind ?
315°.
Question 159-7 : Which of the following values corresponds to a sw wind ?
225°.
Question 159-8 : What is the average wind at fl 160 between zurich and rome. 397 ?
020°/50 kt.
Question 159-9 : Judging by the chart, what windspeeds can you expect at fl 340 above rome. 398 ?
145 kt.
Question 159-10 : Select from the map the average wind for the route frankfurt rome at fl 170 . 408 ?
230/40.
. 465.at fl180 you will find an average wind from 235° and a speed of 15 + 15 + 35 + 50 + 70 / 5 = 37 kt..closest answer is 230°/40 kt.
Question 159-11 : At 40°n 70°w, the forecast wind is. 416 ?
270°/95 kt.
Question 159-12 : A layer is conditionally unstable if the air ?
Is unstable for saturated air and stable for dry air.
.if the environmental lapse rate elr is more than 3°c/1000 ft dry adiabatic lapse rate the environment is unstable...if the environmental lapse rate elr is less than 1.8°c/1000 ft saturated adiabatic lapse rate the environment is stable...but..if the environmental lapse rate elr is more than 1.8°c/1000 ft but less than 3°c/1000 ft, we have conditional stability. stable if air is dry unsaturated..or. unstable if air is saturated.
Question 159-13 : A parcel of unsaturated air is lifted to just below the condensation level and then returned to its original level. what is the final temperature of the parcel of air ?
The same as the starting temperature.
.air can hold a certain amount of water depending on it's temperature. warmer air can hold more water vapour than colder air..will climbing, the parcel cools and hold less water vapour. when the parcel comes back at its original level, it will warm and come back in his original state.
Question 159-14 : What characteristic is associated with a temperature inversion ?
Stability.
Question 159-15 : Absolute instability is said to exist whenever the environmental lapse rate ?
Exceeds the dry adiabatic lapse rate
.if the environmental lapse rate elr is more than 3°c/1000 ft dry adiabatic lapse rate the environment is unstable...if the environmental lapse rate elr is less than 1.8°c/1000 ft saturated adiabatic lapse rate the environment is stable...but..if the environmental lapse rate elr is more than 1.8°c/1000 ft but less than 3°c/1000 ft, we have conditional stability. stable if air is dry unsaturated..or. unstable if air is saturated.
Question 159-16 : Which of the following is a possible consequence of subsidence ?
An inversion over a large area with haze, mist.
. 500.sinking air will dissipate cloud, especially at lower levels, and trap any pollution giving poor visibility.
Question 159-17 : What does 'dew point' mean ?
The temperature to which a mass of air must be cooled in order to reach saturation.
Question 159-18 : Which of the following is the definition of relative humidity ?
Ratio between the actual mixing ratio and the saturation mixing ratio x 100
.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.
Question 159-19 : The relative humidity of a sample air mass is 50%..how is the relative humidity of this air mass influenced by changes of the amount of water vapour in it ?
It increases with increasing water vapour.
.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.
Question 159-20 : Relative humidity ?
Changes when water vapour is added, even though the temperature remains constant.
.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.
Question 159-21 : How, if at all, is the relative humidity of an unsaturated air mass influenced by temperature changes ?
It decreases with increasing temperature.
.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.
Question 159-22 : How does relative humidity and the dewpoint in an unsaturated air mass change with varying temperature ?
When temperature increases, the relative humidity decreases, and the dewpoint remains constant.
.relative humidity is a percentage based on how much moisture is in the air versus how much moisture the air can hold..relative humidity will change if moisture is added to or taken from the air mass or if the temperature changes..if temperature increases, relative humidity decreases and if temperature decreases, relative humidity increases..the dewpoint is the temperature that the atmosphere must reach for a parcel of air to become fully saturated. in an unsaturated air mass the dewpoint will remains constant if the temperature changes.
Question 159-23 : When a given mass of air descends, what effect will it have on relative humidity ?
It decreases.
.when air descends, its temperature increases. if temperature increases, relative humidity will decrease.. 501
Question 159-24 : During the late afternoon an air temperature of +12°c and a dew point of +5°c were measured. what temperature change must at least occur during the night in order to induce saturation ?
It must decrease to +5°c.
.if air temperature decreases by 5°c, air temperature will not be saturated 12°c 5°c = 7°c..so, air temperature must decrease to +5°c to become saturated air temperature and dew point must be equal.
Question 159-25 : Which of the following changes of state is known as sublimation in meteorology ?
Solid direct to vapour.
.sublimation is the process in which a material changes from a frozen solid to a gas without passing through the intermediate liquid state.
Question 159-26 : A parcel of moist but not saturated air rises due to adiabatic effects. which of the following changes ?
Relative humidity.
.the absolute humidity is a measure of mass of water vapour per unit volume of air grams per cubic metre and mixing ration is a measure of mass of water vapour per unit mass of air grams per kilogram. these will not change as temperature changes..the relative humidity is a measure of the percentage degree of saturation and this will change as temperature changes.. 501
Question 159-27 : In which of the following changes of state is latent heat released ?
Gas to liquid.
.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.
Question 159-28 : How are high level condensation trails formed that are to be found occasionally behind jet aircraft ?
Through water vapour released during fuel combustion.
.it is the water vapour produced when hydrocarbon fuels are burnt.
Question 159-29 : In an air mass with no clouds the surface temperature is 15°c and the temperature at 1000 m/agl is 13°c. this layer of air is ?
Stable.
.lapse rate is 2°c for 1000 m 3000 ft , so 0.6°c for 1000 ft. we have four possibilities..if the environmental lapse rate elr is more than 3°c/1000 ft dry adiabatic lapse rate the environment is unstable...if the environmental lapse rate elr is less than 1.8°c/1000 ft saturated adiabatic lapse rate the environment is stable...if the environmental lapse rate elr is more than 1.8°c/1000 ft but less than 3°c/1000 ft, we have conditional. stability if air is dry..or. unstability if air is saturated.
Question 159-30 : If a saturated air mass descends down a slope its temperature increases at ?
A lower rate than in dry air, as evaporation absorbs heat.
.relative humidity will change if moisture is added to or taken from the air mass or if the temperature changes..if temperature increases, relative humidity decreases and if temperature decreases, relative humidity increases.
Question 159-31 : Continuous freezing rain is observed at an airfield. which of the four diagrams is most likely to reflect temperatures above the airfield concerned. 297 ?
Diagram 4.
.there are a few basic elements that need to be in place for freezing rain to occur. there must be a thick layer of warm air in the mid layers of the atmosphere. there also must be a very narrow layer of below freezing temperatures at the surface.. 545.the rain is falling into air with a temperature below 0°c.
Question 159-32 : An isothermal layer is a layer of air in which the temperature ?
Remains constant with height.
Question 159-33 : An inversion is a layer of air which is ?
Absolutely stable.
Question 159-34 : The environmental lapse rate in an actual atmosphere ?
Varies with time.
Question 159-35 : The dry adiabatic lapse rate has a value of ?
1°c/100 m.
.the dry adiabatic lapse rate has a constant fixed value of 1°c/100 m 3°c/1000 ft.
Question 159-36 : The dry adiabatic lapse rate ?
Has a constant fixed value.
.the dry adiabatic lapse rate has a constant fixed value of 1°c/100 m 3°c/1000 ft.
Question 159-37 : An air mass is called stable when ?
The vertical motion of rising air tends to become weaker and disappears
Question 159-38 : Advection is ?
Horizontal motion of air.
.advection is horizontal motion of air...subsidence is vertically downwards motion of air...convection is vertically upwards motion of air.
Question 159-39 : Subsidence is ?
Vertically downwards motion of air.
.advection is horizontal motion of air...subsidence is vertically downwards motion of air...convection is vertically upwards motion of air.
Question 159-40 : Rising air cools because ?
It expands.
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