Chapter 8.2 - Atmospheric Fundamentals Flashcards
Name the two main atmosphere layers?
- Troposphere.
- Stratosphere.
Which atmosphere contains most of the weather?
Troposphere.
What happens with temperature in the Troposphere?
As height increases, temperature decreases.
What happens with temperature in the Stratosphere?
In the lower section, temperature remains close to constant.
What’s the name of the boundary between the Troposphere and the Stratosphere?
Tropopause.
What is the average height of the Troposphere?
36 000ft.
True or False. The Troposphere is equal size around the earth?
False. The Troposphere is smaller around the Equator than the North/South Poles.
True or False. The Troposphere contains all water vapour in the atmosphere?
True.
What does ELR stand for?
Environmental Lapse Rate.
Under average conditions where the temperature at sea level is 15°C, at what altitude will the air freeze (0°C)?
7500ft.
What does ISA stand for?
International Standard Atmosphere.
What is the ISA MSL Pressure?
1013 hPa.
What is the ISA MSL Temperature?
+15°C.
What is the ISA Pressure Lapse Rate (2)?
- 30 hPa per 1000ft.
- 1 hPa per 30ft.
What is the ISA Temperature Lapse Rate?
-2°C per 1000ft.
Name four ways heat transfer within the atmosphere?
- Radiation.
- Conduction.
- Convection.
- Advection.
The transfer of heat energy through space by electromagnetic waves from a hot body/substance to a cold body/substance is called what?
Radiation.
The transfer of heat energy through contact from a hot body/substance to a cold body/substance is called what?
Conduction.
The transfer of heat energy within a fluid (air) by movement of the fluid (air) itself is called what?
Convection.
What is the method where heat (energy) is transferred within the atmosphere by vertical movement of heated air?
Convection.
Name two types of weather phenomenon which are caused by Convection?
- Turbulence.
- Cloud Formation/Rain.
What is the method where heat (energy) is transferred within the atmosphere by horizontal movement of heated air?
Advection.
Name two types of weather phenomenon which are caused by Advection?
- Types of Cloud.
- Fog.
The heat required to change states of matter from Solid to Liquid to Gas (and vice versa) with a constant temperature is called what?
Latent Heat.
What is the name given to the process where a matter changes from Liquid to Gas?
Evaporation.
What is the name given to the process where a matter changes from Gas to Liquid?
Condensation.
What is the name given to the process where a matter changes from Liquid to Solid?
Freezing.
What is the name given to the process where a matter changes from Solid to Liquid?
Melting.
What’s the term called when temperature increases as height increases?
Temperature Inversion.
Surface temperatures are at a minimum just after which period of the day?
Dawn.
Surface temperatures are at a maximum at about which period of the day?
1500 LMT.
What is a dry-bulb thermometer used for?
To measure ordinary air temperature.
What is a wet-bulb thermometer used for?
To measure the amount of water vapour in the air.
If humidity is high, what will the evaporation and temperature drop be?
Low.
If humidity is low, what will the evaporation and temperature drop be?
High.
The difference between the wet-bulb and dry-bulb temperature will give you the measurement of what?
Humidity in the air.
When will the wet-bulb, dry-bulb and dew point temperature be equal?
If the relative humidity is close to 100%.
True or False. The dry-bulb temperature is also used to measure the temperature of the air surrounding an Aircraft?
True.
Atmospheric pressure at MSL is 1013 hPa which is equivalent to how many centimetres of mercury?
76.
When two places have different MSL pressures, the pressure difference between them is known as what?
Horizontal Pressure Gradient.
When QNH is set of the pressure-setting subscale of an Altimeter, this will indicate what?
Altitude.
When an Aircraft is on the ground, the QNH can be found by setting the Altimeter to read what?
Elevation of the aerodrome.
How does wind affect the rate of evaporation?
The stronger the wind, the higher the rate of evaporation.
What is Saturated Air?
When the air contains the maximum amount of water vapour at a given temperature.
Relative Humidity is expressed as what?
Percentage (%).
Relative Humidity is the ratio between what?
Amount of water vapour in the air to the maximum amount of water vapour the air can hold at that temperature.
For cloud to form, condensation must occur, for condensation to occur, the relative humidity must be what?
100%.
Define Dew-point Temperature?
The temperature at which the air can no longer hold all water vapour.
The Dew-point Temperature is a common indicator of what?
Atmospheric Moisture/Humidity.
Why is the Dew-point Temperature extremely important in aviation meteorology?
It is the best indicator for fog formation and the height of clouds to form.
If temperature is constant, what will happen to density and pressure?
Density will increase as the pressure increases.
If pressure is constant, what will happen to density and temperature?
Density will decrease as the temperature increases.
