Turbulence Flashcards
(27 cards)
What causes convective (thermal) turbulence?
Unequal heating of the earth’s surface
Which areas heat up faster, darker or lighter areas?
Darker areas such as soil, rocks, and sand
What happens to warm air during convective turbulence?
It rises and is replaced by cooler sinking air
What is the typical diameter of cells in convective turbulence?
Hundreds of feet
In unstable conditions, how fast can these cells rise?
A few thousand feet per minute
Fill in the blank: Darker areas heat up faster than _______.
lighter areas such as grass or water
What types of clouds indicate that convective turbulence is happening?
Fair weather cumulus (CU), towering cumulus (TCU), altocumulus castellanus (ACC), cumulonimbus (CB)
These cloud types are associated with convective activity and potential turbulence.
What do TCUs indicate?
Moderate to severe turbulence may be present
TCUs are a specific cloud type that signals possible turbulence conditions.
What is a recommended strategy to avoid convective turbulence?
Fly above the cloud formations or during early morning/late evening
Flying at these times can help avoid turbulence associated with convective clouds.
What causes turbulence in the lower levels of the atmosphere?
Cold air moving over a warm surface
This temperature difference causes the air to rise faster, leading to turbulence.
What is the expected flight condition when flying below clouds?
Bumpy flight
Turbulence is more likely to occur in lower levels, especially when cold air interacts with warm surfaces.
Fill in the blank: __________ can indicate the presence of convective turbulence.
Towering cumulus (TCU)
TCUs are particularly notable for indicating moderate to severe turbulence.
What is virga?
A weather phenomenon where precipitation falls from a cloud but evaporates or sublimates before reaching the ground.
Virga creates streaks or wisps in the sky.
In which regions is virga often seen?
Dry or warm regions.
Virga occurs when atmospheric conditions allow for evaporation or sublimation of precipitation.
What hazardous weather phenomenon can virga sometimes lead to?
Microbursts.
Microbursts are dangerous to aviation due to sudden changes in wind speed and direction.
True or False: Virga is a type of precipitation that reaches the ground.
False.
Virga does not reach the ground as it evaporates or sublimates in the atmosphere.
Fill in the blank: Virga creates streaks or _______ in the sky.
wisps.
What is virga?
Rain that evaporates before reaching the ground.
Virga occurs when precipitation falls through a layer of dry air and evaporates, leading to specific atmospheric effects.
How does virga influence downdrafts?
Virga produces strong downdrafts as the rain drags the air downward.
This phenomenon is similar to a microburst.
What happens to rain falling through a drier layer of air?
The rain evaporates, causing cooling of the descending air.
This cooling effect contributes to the formation of strong downdrafts.
What occurs when cooled air continues downward without rain?
It leads to the presence of a strong downdraft.
The absence of visible rain can make it difficult to detect the downdraft.
What effect does the strong downdraft have when it reaches the surface?
It creates divergence of the air, leading to wind shear.
Wind shear can significantly impact aviation and weather conditions.
What are the characteristics of light turbulence?
Slight erratic changes in attitude and/or altitude, less than 15 KT airspeed fluctuation.
Light turbulence is often barely noticeable to pilots.
Define moderate turbulence.
Greater intensity than light chop, usually causes bumps or jolts but aircraft remains in control at all times.
Moderate turbulence can be felt by passengers and may require attention from the flight crew.
