The Atmosphere Flashcards
What happens to the temperature from tropopause at FL650?
Varies but remains fairly constant
Which set of conditions at an aerodrome would be most limiting to aircraft performance during take off?
High elevation, low QNH, high temperature
Where would you be most likely to observe a subsidence inversion?
Northern continents in winter and subtropical ocean areas
What gas in the atmosphere can cause inflight problems (chest, breathing-throat)?
Ozone
Apart from radiation, convection, and the release of latent heat, what other factors influence the exchange of heat between the surface and the atmosphere?
The process of conduction is the primary mechanism by which heat is transferred from the surface vertically within the atmosphere to low or medium levels.
What is a correct statement regarding the cooling/warming of the Earths surface by radiation ?
More heat is radiated into space from a warm surface than from a cold surface
A high pressure that is weakening with altitude and turns into a low is called ?
Cold high
At FL180, the air temperature is -35c. The air density at this level is ?
Greater than the density of the ISA atmosphere at FL180
(Density will be greater as it’s colder)
How is the heat of the earth predominately transferred upwards and exits the atmosphere
Terrestrial radiation
Which FL corresponds with the 300hPa pressure level ?
FL 300
What is the corrects statements regarding conduction ?
1) conduction has less of an effect in heating of the troposphere in comparison to convection
2) at night, the air can be cooled by conduction
At what altitude is the pressure 50% in ISA ?
18,000 ft
Half the mass of the atmosphere is found in the lowest…?
5 km
The station pressure used in surface weather charts is…?
QFF
(So QFE reduced to MSL with regard to actual OAT)
What is the vertical temperature lapse rate, up to 11km, in the standard ICAO atmosphere ?
6.5c per 1000m
(1000m3.2=
3200ft. 3200/1000 = 3.2 3.2-2= -6.4)
In the ICAO standard atmosphere the decrease in temperature with height below 11km is…?
0.65c per 100m
(6.5c/km) (2c per 1000ft, 0,65 per 100m)
What happens at the tropopause ?
There is an abrupt change in the environmental lapse rate of air temperature
An isothermal layer, is a layer of air in which the temperature…?
Remains constant with height
What is a correct statement regarding the transfer of heat in the atmosphere?
The air at the surface can be cooled or warmed by the process of conduction, which is the molecular transfer of heat between the surface and the air in contact with it
The tropopause is a level at which temperature…?
Temperature ceases to fall with increasing height
Which FL corresponds with the 500 hPa pressure level?
FL 180
The atmospheric density is expected to be 50% of the density at MSL in ISA at?
22,000 ft
(Don’t confuse air pressure and density. Air pressure is MSL value at 18,000)
What is the ISA deviation at FL390 where the OAT was -56c?
+0.5c
Which gas component of the air has the greatest importance for the weather on earth?
Water vapour
The earth is heated by convection. What are the other sources that contribute to the distribution of heat ?
Conduction, turbulent mixing and radiation.
In mid-latitudes, what happens to the air temperature as altitude increases between the tropopause and FL650?
It varies, but generally remains relatively constant
The tropopause is a (1)………. between the troposphere and the stratosphere. Its height at the equator is (2)……… than over the poles and the temperature is (3)……. Compared to the poles.
1) boundary
2) higher
3) lower
What is the most important constituent in the atmosphere from a weather standpoint?
Water vapour
What is the ISA deviation at FL370 where the OAT was -45c
+11.5c
(Above 36,000 = 56.5c. 56.5c-45c = 11.5c)
What, approximately, is the average height of the tropopause over the equator ?
16km
The cause of the potential difference between the earth and the atmosphere which causes thunder is…?
The different distribution of electrically charged particles between the ground surface and the ionosphere
What is a correct statement regarding a valley inversion overnight along mountain slopes?
Over night, cool dense air as a result of radiation cooling will descend along the mountain slopes into the basin and lead to the development of a valley inversion
The absence of regular convection in the stratosphere due to warmer layers higher up and cooler ones lower down makes this part of the earths atmosphere…?
Generally turbulence free
What statement is correct regarding the cooling/warming of the earths surface by radiation?
The earth is heated by short wave radiation from the sun, but cooled by its own long wave radiation into space
A flight in summer was planned to take-off from Phuket, Thailand at 08:30 LT, but the departure was delayed to 11:00 LT. what could happen to the take off performance because of this? The climb performance during takeoff (1)…… because the air density (2)…….
1) degrades
2) decreases
What is a correct statement regarding the air above the tropopause?
The layer just above the tropopause is absolutely stable
The destination airport has an elevation of 210 ft BELOW MSL. A airport METAR gives
Q1018. What is correct ?
QFF is greater than QNH
(210/30 = 7hpa
1013+7hpa = 1020hpa
QFF is greater than QNH)
The base of the stratosphere is situated where heating by conduction from above and convection from below balance out. It is..?
Lower near the poles because of lower ground temperatures
During a sunny day and at the same latitude, over which of the following positions will the warming of air just above the surface be the greatest? Above…?
Rocks
(Rocks are black on average so they absorb most of the heat)
The 0c isotherm is a forecast to be at FL50. At what FL would you expect a temperature of -6c?
FL80
(If temp at FL50 is 0c we know that temp decreases at a rate of 2c per 1000ft with increasing altitude, we know that -6 will be 3000ft higher than FL50. So -6c at FL80)
What is a correct statement regarding the ozone layer in the atmosphere
Ozone is present at jet cruise altitudes in the troposphere and the lower stratosphere, at concentrations that are hazardous to humans
