Cloud Flashcards
Describe the relationship between stability of air and cloud type in relation to poles AND equator
Air from the equator traveling poleward = stable/low cloud
•Because decreasing surface temperature cools it
•Air from the poles traveling to the equator = Unstable
•Because increasing surface temperature warms it
Describe the relationship between stability of air and cloud type (stable air)
Stable clouds = Cirrostratus, Altostratus, Nimbostratus, Stratocumulus, Stratus
Describe the relationship between stability of air and cloud type (unstable)
Unstable clouds = Cirrocumulus, Altocumulus, Cumulonimbus, Towering Cumulus, Cumulus
List the vertical extents of the three main cloud layers in mid latitudes
Low cloud - below 7000
Middle cloud - 7-23,000ft
High cloud - 17,000-45000ft
List the vertical extents of the three main cloud layers in tropical latitudes
Low cloud - below 7000ft
Middle - 7000 - 25,000ft
High - 20,000 - 60,000ft
State the difference between the Lifting Condensation Level (LCL) and the Convective Condensation Level (CCL)
LCL = Height all non-convective cloud will form through forced lifting.
•Forced up by fronts, hills, turbulence, convergence
•CCL = Height convective cloud forms (thermals rising air mass)
•Raises temperature further away from dew point
•Therefore CCL is always higher than LCL
Demonstrate the use of simple formulae to calculate the LCL and CCL
CCL = 400 x (Surface Temp – Dew Point)
•LCL = 400 x (Surface Temp – Dew Point) x 0.85
Describe cirrus
White
•High level
•Fibrous hair-like cloud
•Narrow bands
•Stable
•Ice crystals
Describe cirrocumulus
White
•High level
•Sheet cloud
•Ripples
•Conditional instability
•Ice crystal
Describe cirrostratus
White
•High level
•Transparent
•Only cloud to create solar halo
•Stable
•Ice crystals
Describe altocumulus
White/grey
Middle level
Unstable
Droplets/ice crystals
Describe altostratus
Greyish/bluish
Middle level
Sun barely visible
Stable
Droplets/ice crystals
Nimbostratus
Grey/dark
Low level
Conditional instability
Droplets/snow/Supercooled water droplets
Thick
Nimbostratus
Often forms along warm or occluded fronts
Form through the deepening and thickening of an altostratus cloud
Describe stratocumulus
Grey/white
Low level
Rolled layer cloud
Stable
Droplets
Describe stratus
Grey
Low level
Layer cloud
Stable
Droplets
Cumulus
White
Low level
Heaped cloud
Conditional instability
Cumulonimbus
Very dark
Low level
Heaped cloud
Large vertical extent
Anvil on top
Unstable
Describe conditions for each cloud in regards to 10 clouds (Ci, Cs, CC, AS, AC, NS, Sc, St, Cu, Cb) turbulence
Ci - nil
Cs - nil
CC - light
As - light/moderate
Ac - light/moderate
NS - moderate
Sc - light
St - nil
Cu - Moderate/severe
Cb - moderate/severe
Describe conditions for each cloud in regards to 10 clouds (Ci, Cs, CC, AS, AC, NS, Sc, St, Cu, Cb)
Icing
Ci - nil, trace
Cs - nil, trace
CC - nil, trace
As - light
Ac - light
NS - moderate/severe
Sc - light/moderate
St - light
Cu - moderate
Cb - Moderate/severe
Describe conditions for each cloud in regards to 10 clouds (Ci, Cs, CC, AS, AC, NS, Sc, St, Cu, Cb)
Precipitation
Ci - nil
Cs - nil
CC - nil
As - light/moderate
Ac - light/moderate
NS - heavy precipitation
Sc - drizzle/light
St - drizzle/light
Cu - heavy showers
Cb - heavy showers
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each Asperitas
Unstable
•Severe Turbulence
•Occurs within Altostratos and Stratocumulus
•Most likely cause is gust front
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each (mammatus)
Unstable
Severe turbulence
Forms under Cb
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each (altocumulus lenticularis)
Ragged edges indicate turbulence
•Formed from mountain waves above mountain height
Ragged edges indicate turbulence
•Formed from mountain waves above mountain height
(Rotor cloud)
Forms under lenticular clouds
Strongest turbulence in first waves
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each
(Kelvin helmholtz waves)
Caused by vertical windshear
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each
(Altocumulus Castellanus)
Unstable
Cumuliform tops rising from a common base
Moderate turbulence
Identify the following cloud sub-sets and outline the atmospheric conditions indicated by each (banner cloud)
Uplift of cloud on sheltered lee side
Reduced pressure downwind
Explain cloud dispersal (direct warming)
Direct solar radiation disperses cloud from top down
•Terrestrial radiation increases surface temperature
•Moves dew point further away from temp dispersing cloud
Explain cloud dispersal process: sinking of air
Air containing cloud sinks and so the cloud has more pressure thus warms due to Adiabatic warming, as parcel descends dew point remains constant but temp increases so Dew point moves away from temperature dispersing cloud.
Explain cloud dispersal process: Mixing with clear air
Injects dry air (entrainment - mixing dry air with humid air), lower RH causes evaporation
Describe the effect of latent heat release on stability inside a cloud and its influence on resulting cloud type (ATPL)
Releasing latent heat increases temperature
•Increases instability
•Results in cumuliform cloud or Cb
With regard to orographically developed cloud, explain the influence of stability/instability and different surface dew point values on the type and vertical extent of any cloud form (ATPL)
Stable = Shallow vertical extent (stratus)
•Unstable = Deep vertical extent (cumulus)
•Closer dew point is to surface temp = lower cloud base
With regard to orographically developed cloud, describe the formation and characteristics of lenticular cloud (ATPL)
Formed due to mountain waves
•Lens shaped clouds
•Found above mountain tops in crests of waves
•Can be found up to and above tropopause
