Cloud Formation and Fog Flashcards
How can condensation occur at less than 100% relative humidity?
Abundance of Condensation Nuclei
What are the 5 processes which result in the ascent of air and adiabatic cooling?
- Convection
- Mechanical Turbulence
- Frontal Lift
- Orographic Lift
- Convergence
Evaporation of falling rain and Advection over a colder surface
What are the 4 families of clouds?
- High Clouds
- Middle Clouds
- Low Clouds
- Clouds of Vertical Development
What family of clouds is based 20 000ft to 40 000ft?
High Clouds
What family of clouds is based 6 500ft to 20 000ft?
Middle Clouds
What family of cloud is based on the surface to
6 500ft?
Low Clouds
What family of clouds is based 1 600ft up?
Clouds of Vertical Development
This cloud appears as white curly streaks across the sky.
Cirrus (CI)
This cloud appears as a whitish veil through which the sun and moon can be seen, often surrounded by a halo.
Cirrostratus (CS)
This is a somewhat rare cloud. It appears as a white sheet with a pebbly pattern.
Cirrocumulus (CC)
This is a layer cloud with no definite pattern. It is steely or bluish in colour and, as seen from a particular place, may cover the entire sky. Sometimes sun or moon can be seen through it but there are no halos.
Altostratus (AS)
This is a layer or series of patches of rather flattened, rounded masses of cloud. The cloudlets may be arranged in groups, lines or waves and are sometimes so close that their edges join.
Altocumulus (AC)
This cloud is pronounced with turrets building upward. It implies considerable instability in the cloud layer and may develop into cumulonimbus.
Altocumulus Castellanus (ACC)
A uniform layer of very low cloud that may appear in extensive sheets or irregular patches.
Stratus (ST)
This is the main precipitation cloud: continuous rain, snow, freezing rain, etc, may be encountered when flying in or below it. It is an extensive layer, uniformly dark in colour, based near or at the ground.
Nimbostratus (NS)
The bottom of this cloud is clear-cut, wavy or rolled appearance. Appears as an extensive sheet, but sometimes well defined breaks between the rolls. It may give little precipitation.
Stratocumulus (SC)
These are fluffy white clouds that form in the top of convective currents. Their edges are hard and clear-cut in appearance and their tops are rounded.
Cumulus (CU)
Clouds that have grown considerable height but still have clear-cut rounded tops. Showers may fall from this.
Towering Cumulus (TCU)
This cloud loses its hard, clear-cut appearance and frays our into a widespread, white, fibrous structure, often called an anvil or thunderhead. Heavy precipitation in the form of rain or hail showers may be seen pouring out of it.
Cumulonimbus (CB)
ADF and LF radio interference occurs in this type of cloud.
High Clouds
Infrared sensors are affected by this type of cloud.
Middle Clouds
What determines whether the cloud forms in horizontal sheets (stratiform) or builds up in towers (cumuloform)?
The stability or instability of the air
What is the major mechanism that causes condensation?
Adiabatic Expansion
What is the word that is added to the names of clouds that normally produce precipitation?
Nimbus
What determines the intensity of precipitation?
- Strength of the updraft within the cloud
- Cloud’s vertical thickness
- Water content
What are the 2 reasons for the importance of the vertical thickness of clouds?
- Warm Air; Low Cloud Base
- Ice crystals required; cloud top must be below freezing
This precipitation is of short, duration, beginning and ending abruptly. Falls from cumuloform cloud.
Showery
This precipitation is not showery, but has stopped and recommenced at least once during an hour. Falls from layer clouds.
Intermittent Precipitation
This precipitation is not showery but continues without a break for at least an hour. Falls from layer clouds.
Continuous Precipitation
