Cloud Classification Flashcards
Height is..
The vertical distance from the point of observation to the base or top of a cloud
Average tropopause heights for polar, temperate, and tropical?
Polar: -8km (25,000ft)
Temperate: -13km (45,000ft)
Tropical: -18km (60,000ft)
What are the three etages?
High
Mid
Low
What are the heights of the etages in temperate regions?
High 20,000-40,000ft / 6-12km
Mid 6,600-19,900ft / 2-6km
Low near surface- 6,500ft / (nr sfc) -2km
What clouds are associated with each etage?(3)(4)(7)
High: CI, CS, CC
Mid: AC, AS, NS, ACC
Low: SC,ST,CU,CB,SF,CF,TCU
What are the high etage clouds? (3)
Cirrus
Cirrostratus
Cirrocumulus
Name and describe!
Cirrus (CS):
Detached clouds
White delicate filaments
White patches or narrow bands, hairlike
Fibrous or silky appearance
Name and describe!
Cirrostratus (CS):
Transparent
Whitish veil of cloud
Great horizontal extent
Totally or partly covers sky
Generally shows halo
Edge often frayed with CI
Name and Describe!
Cirrocumulus (CC):
Thin white patches (no shade), sheet or layer
Small elements shaped like ripples or grains
More or less regular arranged
What are the mid etage clouds? (4)
Altocumulus AC
Altostratus AS
Altocumulus Castellanus ACC
Nimbostratus NS
Name and describe!
Altocumulus (AC):
White or grey or both
Patch, sheet, or layer
Generally shaded
Rounded masses or rolls
Usually regular arranged elements
Sometimes partly fibrous
Name and describe!
Altostratus (AS):
Greyish or bluish
Sheet or layer
Striated, fibrous, or smooth
Parts are thin enough to reveal sun (ground glass)
Thicker than CS
Name and describe!
Altocumulus Castellanus (ACC):
A species of Altocumulus
Has cumuliform protuberances in the form of towers or turrets
Has a common base
Turbulence will increase as someone approaches the base
Name and describe!
Nimbostratus (NS):
Grey layer, usually darker
Appearance diffused by continuous precipitation
Thick enough to blot out the sun
Base usually in the lower etage
What are the low etage clouds? (7)
Stratocumulus SC
Stratus ST
Stratus Fractus SF
Cumulus CU
Cumulus Fractus CF
Towering Cumulus TCU
Cumulonimbus CB
Name and describe!
Stratocumulus (SC):
Grey and/or white
Patches, sheet, or layer
Rounded masses or rolls
May or may not be merged
NON FIBROUS
Finger rule: More than 3 fingers
Name and describe!
Stratus (ST):
Generally grey
Uniform base (28)
Sun outline clear (32)
Does not produce halo except at very low temps
Name and describe!
Stratus Fractus (SF):
Species of ST
Irregular ragged shreds of ST
Sometimes forms under clouds giving precipitation (pannus)
Name and describe!
Cumulus (CU):
Detached clouds
Generally dense with sharp outlines
Develops vertically in forms of mounds, domes, or towers
Bulging top often resembles cauliflower
Sunlit parts of cloud brilliant white
Bases dark and nearly horizontal
Name and describe!
Cumulus Fractus (CF):
Species of CU
Small cumulus clouds with ragged edges
Changes very rapidly
Sometimes, forms in precipitation
Name and describe!
Towering Cumulus (TCU):
Rule of thumb: height is twice the width of the base
Cumulus of great vertical extent
Bulging tops resemble cauliflower
May give showers
May develop into CB
Name and describe!
Cumulonimbus (CB):
Heavy dense cloud of great vertical extent
Form of mountain or tower
Upper portion smooth, fibrous, or striated
Upper parts spreads into anvil or vast plume
Base of cloud very dark
Lightning and Thunder
Bases in the low etage with tops extending through all three levels
Icing and turbulence severe within the cloud
