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Chapter 5 Clouds
What are the Basic Elementsof Weather & Climate
(list 6)
Wind
Temperature
HumidityClouds
PrecipitationPressure
Precipitation
List 6 forms of precipitation:
What is graupel?
Clouds: • A visible aggregate of minute droplets of
water or tiny ice crystals (or both).
For Clouds to form, TWO conditions must exist:
1. Air is lifted, cooled adiabatically, until the air is SATURATED. Then water vapor can
condense into water droplets
What do all these pictures have to do with clouds?
Cloud Condensation Nuclei
2. Water vapor needs to condense (stick) onto a SURFACE.
A “surface” can be microscopic dust particles, smoke, salt, pollen, volcanic ash, soot from combustion or forest fires.
Without the condensation nuclei surface, the air needs to be greater than 100% humidity or very, very low temperatures (so the water vapor has very little KE and the particles can slow down enough to collide and stick together.
2 types of condensation nuclei
Hygroscopic nuclei• “Water-seeking”• Effective sites for water
vapor to condense into droplets.
• Form larger water droplets
• Example: salt particles
Hydrophobic nuclei• “water-repelling”• Not efficient for forming
water droplets • only if the relative humidity
reaches 100%• Form smaller droplets
Initially, cloud droplet formation is
rapid,but it slows as the
water vapor in the air is used up
The size of cloud droplets can vary.
It takes about a million cloud
droplets to form a single raindrop.
Classification Cloud Types Height Composition Description
High Clouds Prefix: ____________ _____________meters
Middle Clouds Prefix: ___________ ____________meters
Low Clouds Prefix: ____________ _____________meters
Clouds of Vertical
Development
Cloud Types: height and form
Pg. 134
Cirrus Clouds
Cirrostratus
Cirrocumulus
AircraftContrails:
Condensation trails of ice crystals
Altocumulus Altostratus
Nimbostratus
Cumulus Clouds
Cumulonimbus:Dark, dense, towering clouds with anvil-tops that reach heights of 30,000 ft. and produce thunderstorms, hail and tornados.
• Why are high clouds always so thin
compared to low clouds?
Lenticular
Clouds
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