C07 - Humidity Flashcards
Define Humidity?
The amount of Water Vapour in the Atmosphere.
What is the term given when changing Ice to Water and the Latent Heat process (2)?
- Melting.
- Latent Heat Absorbed.
What is the term given when changing Water to Gas and the Latent Heat process (2)?
- Evaporation / Vapourisation.
- Latent Heat Absorbed.
True or False. For any given Temperature or Pressure, the air can only contain a certain amount of Water Vapour?
True.
‘____’ Air can hold a lot more Water Vapour than ‘____’ Air (2)?
- Warm.
- Cold.
For any given ‘____’, the air can only contain a certain amount of Water Vapour?
Temperature or Pressure.
What is the term given when changing Gas to Water and the Latent Heat process (2)?
- Condensation.
- Latent Heat Released.
For Condensation to occur the Air must be ‘____’?
Cooled.
When Condensation can be seen with the human eye, what phenomenon can we see (4)?
- Steam.
- Dew.
- Fog.
- Clouds.
What is the term given when changing Water to Solid and the Latent Heat process (2)?
- Freezing.
- Latent Heat Released.
True or False. Liquid form can still exist below 0°C?
True.
What is the term given to a Liquid which is below 0°C?
Supercooled Water Droplets.
What is the term given when changing Gas to Solid and Solid to Gas?
Sublimation.
True or False. Sublimation can also be seen at high Altitudes when you emerge from icing conditions?
True.
How is Humidity measured?
By Hygrometers.
Name two types of Hygrometers?
- Digital.
- Psychrometer.
What is the name of the two thermometers found in the a Psychrometer?
- Dry Bulb.
- Wet Bulb.
Define Absolute Humidity?
A quantity representing the actual amount of Water Vapour in a Gas.
What is the measurement for Absolute Humidity?
g/m³.
Define Specific Humidity?
The ratio of Water Vapour content to the Total Air Content on the mass basis.
The Humidity Mixing Ratio ‘____’ with a decrease in Atmospheric Pressure?
Increases.
The Saturated Humidity Mixing Ratio is maximum when the air is ‘____’?
Saturated.
‘____’ Temperatures require more Water Vapour to reach saturation?
Higher.
Lower Temperatures require ‘____’ Water Vapour to reach saturation?
Less.
Define Relative Humidity?
The amount of Water Vapour present in the air, expressed as a percentage of the amount required to reach saturation at the same Temperature.
When the Temperature of the Air decreases, Relative Humidity ‘____’?
Increases.
When the Temperature of the Air increases, Relative Humidity ‘____’?
Decreases.
Define Dew Point?
The Temperature to which air must be cooled for it to become saturated.
What is the formula to calculate Cloud Base?
(Temperature – Dew Point) x 400.
When the Temperature value is higher than the Dew Point value, what are the conditions of the current Air?
- Dry Air.
- Clear Skies.
When the Dew Point value is close to the Temperature value, what are the conditions of the current Air?
- Humid Air.
- Low Cloud.
When the Dew Point and Temperature values are equal, what are the conditions of the current Air?
- Saturated Air.
- Fog and Mist.
