1. Observing Climate - Upper Air
Water (Con’t)
Clouds
Types - Classification
Base height
Coverage
Science Concepts
Definition
The Earth System (Kump, Kastin & Crane)
• Chap. 3 (pp )

2. Observing Climate - Clouds
What do we want to know about clouds and cloud cover?
What do we want to know about clouds and cloud cover?
• Rain or no rain
• Liquid or ice
• Height
• Percentage of sky covered by cloud
• Formation process

3. Observing Climate - Clouds
Definition
• Clouds are water vapor that has changed
to a solid (deposition) or liquid
(condensation) in the atmosphere
Classification
• Named by formation mechanism (causes
shape), by level, by rain or no rain, etc.
• Several root words from Greek are key to a cloud classification scheme
- cirro > Hair like, fibrous aspect and/or milky sheen
- cumulo > Puffy, detached modules
- strato > Layer like
- nimbo > Rain
A stanza of “The Cloud”
I am the daughter of Earth and Water,
And the nursling of the sky;
I pass through the pores of the ocean
and shores;
I change, but I cannot die.
Percy Bysshe Shelley

4. Observing Climate - Clouds
Classification (Con’t)
• Root words that refer to cloud height
- Cirriform
> Cloud types with the highest altitude bases; composed of ice
crystals, very cold, bases 6 km and higher
- Altoform
> Middle level clouds with intermediate altitude bases; composed of
ice, super-cooled water drops or drops above freezing, bases
between 2 and 6 km
- Stratoform
> Cloud types with lowest altitude bases; usually “warm” (above
freezing) clouds composed of water drops above freezing (but may
be ice crystals in winter), bases from the surface to 2 km
• Clouds with Vertical Development
- Composed of all possibilities above depending on cloud temperature

5. Observing Climate - Clouds
Classification (Con’t)
• Examples of Cloud Names - Who and when
defined
- High Clouds
> Cirrus (Ci) - Howard (1803)
> Cirrostratus (Cs) - Howard (1803)
> Cirrocumulus (Cc) - Howard (1803)

6. Observing Climate - Clouds
Classification (Con’t)
• Examples of Cloud Names
- Middle Clouds
> Altostratus (As) - Renou (1870)
‡ Middle clouds composed of gray or blue
layers of uniform appearance. Snow or
rain may fall from these clouds
> Altocumulus (Ac) - Renou (1870)

7. Observing Climate - Clouds
Classification (Con’t)
• Examples of Cloud Names
- Low Clouds
> Stratus (St) - Howard (1803)
> Stratocumulus (Sc) - Kaemtz (1841)
> Nimbostratus (Ns) - International
Commission for the Study of Clouds
(1930)
‡ Dark, gray clouds characterized by
more or less continuously falling
precipitation, usually rain, not
accompanied by lightning, thunder,
or hail

8. Observing Climate - Clouds
Classification (Con’t)
• Examples of Cloud Names
- Clouds with Vertical Development
> Cumulus or Fair weather cumulus
‡ Individual, detached heaps or towers
that are usually dense and well
defined
> Cumulus Congestus
‡ Individual, detached
domes or towers;
usually dense and
well defined
> Cumulonimbus (Cb) -
Weilbach (1880)
‡ Exceptionally dense and vertically developed clouds,
often with anvil shaped top, frequently
accompanied by heavy showers,
lightning, thunder and sometimes hail

9. Observing Climate - Clouds
Cloud Observations
• Ceiling - Height of the lowest layer of clouds above the surface that are either
broken or overcast
• Ceilometer
- Automatic instrument used to record ceiling, i.e.,
the altitude of the lowest cloud layer
- Consists essentially of a projector, detector, and
recorder
- Optical ceilometer uses
triangulation to determine
height of a spot of light
projected onto the base of
cloud
- Laser ceilometer determines
height by measuring the time
required for a pulse of light to
be scattered back from the cloud base
Laser Ceilometer

10. Observing Climate - Clouds
Cloud Observations (Con’t)
• Cover
guides/maps/sfcobs/wx.rxml