Clouds

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Clouds

• Clouds are formed by the condensation of water
  vapor on tiny particles in the air

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Recipe for a cloud

• Need a source of water vapor
• Condensation nuclei- tiny particles upon which
  the water vapor can condense
• There has to be a change in temperature or air
  pressure

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Ways to break it down

• 3 forms
• Cirrus a curl of hair
• high, white, thin, feathery
• Cumulus puffy, pile
• flat base, cauliflower structure
• Stratus layered or blanket like
• cover most of the sky

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Cirrus
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Cumulus
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Stratus
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• 3 heights
• High Clouds
• gt 6000 meters
• Middle Clouds
• 2000 6000 meters
• Low Clouds
• lt 2000 meters

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High Clouds

• Mostly made of ice crystals
• Thin and white
• 1. Cirrus
• 2. Cirrocumulus
• Cirrocumulus are often associated with large
  weather systems
• 3. Cirrostratus
• Halos around the sun, bright arcs, and brilliant
  spots are optical phenomena associated with
  sunlight passing through the ice crystals
  composing the cirrostratus

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Middle Clouds

• Have the prefix alto as part of their name
• 1. Altocumulus
• Larger and denser
• 2. Altostratus
• Grayish sheet covering sky
• Sun or moon visible as a bright spot

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Altocumulus
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Altostratus
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Low Clouds

• 1. Stratus
• Fog-like layers
• Light precipitation
• 2. Stratocumulus
• patchy

• 3. Nimbostratus
• Nimbus rain cloud
• 4. Cumulus
• Fair weather

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Nimbostratus
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Clouds that dont fit in a category

• Cumulonimbus
• Storm clouds start at base levelbut can grow
  and grow up to top of troposphere
• animation of formation of a cloud

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Cumulonimbus
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Cumulonimbus with anvil top
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Cumulonimbus with anvil top
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Mammamtus
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Fog

• Fog and cloud are the same thing. The Difference
  is where and how they form
• Cooling humid air moves over cool land
• Cold cant hold!
• Advection Fog
• Evaporation cool air moves over warm water
• Looks like the lake is steaming
• Radiation Fog

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How Precipitation Forms

• There needs to be a surface for the water vapor
  to collect on..condensation nucleus
• If there are no condensation nuclei, then the air
  must be supercooled in order to be saturated
  enough to produce condensation

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Supercool

• Cloud droplets do not freeze _at_ 0oC
• They want to
• They need condensation nuclei to freeze onto
• The water in air of this temperature is said to
  be supercooled
• Cloud droplets will freeze without condensation
  nuclei _at_ -40oC

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Collision-coalescence

• Once a drop formsit collides and coalesce (joins
  together) with smaller drops

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Forms of Precipitation

• Depends on the temperature
• Rain
• Snow
• Sleet
• Glaze
• Hail

animation of precip. animation of hail
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Rain
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Snow
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Sleet
Little particles of ice (Refreezing rain)
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Glaze
Supercool Rain freezes on contact
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Hail
Cumulonimbus clouds ice pellets that grow as
they fall through the cloud, but get tossed back
up by the convection current (updraft). Each
trip up/down, a new layer is added