Cloud Classifications Flashcards
What are the 5 steps to cloud formation?
- Warm air rises and cools
2 The RH of the air increases - Eventually, air becomes saturated and cannot support water in vapour form
- Water vapor condenses on smoke, dust, salt and other small particles
- Millions of small water drops of liquid water collect to form a cloud.
What are the 5 mechanisms in the formation of clouds?
- Convection
- Widespread Ascent
- Turbulence
- Atmospheric Wave Motion
- Orographic Lifting
What type of cloud is typically formed with convective ascent?
Cumuliform
What is atmospheric motion and what type of cloud is formed?
An oscillatory pattern of airflow when:
1) Strong wind blowing at right angles to a mountain range
2) Windspeed increasing with height to reach at least 25 kts at the top
3) A stable layer at the mountain top height
- Lenticular clouds typically formed
What is orographic lifting and what clouds does it typically form?
- Air forced to rise when it encounters a mountain barrier
- Depending on stability of atmosphere, stratiform or cumuliform cloud will form.
What is widespread ascent and what cloud does it form?
- Large air masses rising over wide areas.
- Cold fronts will form cumuliform type clouds
- Warm fronts will cause stratiform type clouds.
What is turbulent mixing and what type of cloud is formed?
Turbulence mixing cool air and water vapour results in stratocumulus cloud between the condensation and the inversion.
What is conductive cooling?
- Likely the result in formation of fog, dew and frost on the ground.
What are some ways of determining cloud height?
- Human observation
- Clinometer gun (used at night)
- Ceilometer
What are clouds typically composed of?
- Water droplets
- Supercooled water droplets
- Ice crystals
What temperature can supercooled water droplets exist down to?
-40 C
What altitudes are low, middle or high clouds classified into?
Low: < 8000 ft
Middle: 8000 ft to 20,000 ft
High: > 20,000 ft
What are the high level cloud? What are they typically composed of?
- Cirrus (Ci)
- Cirrostratus (Cs)
- Cirrocumulus (Cc)
- Typically composed of ice crystals
What are the middle level clouds? What are they typically composed of?
- Altostratus (As)
- Altocumulus (Ac)
- Nimbostratus (Ns)
- Composed of supercooled water droplets and ice crystals.
What are the low level clouds?
- Stratus (St)
- Cumulus (Cu)
- Stratocumulus (Sc)
- Cumulonimbus (Cb)
- Water droplets/supercooled water droplets depending.
